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Component Manager Reference

Framework
CoreServices/CoreServices.h
Declared in
Components.h

Overview

You can use the Component Manager to allow your application to find and utilize various software objects (components) at run time. You can create your own components, and you can use the Component Manager to help manage your components. A component is a piece of code that provides a defined set of services to one or more clients. Applications, system extensions, as well as other components can use the services of a component. A component typically provides a specific type of service to its clients. For example, a component might provide image compression or image decompression capabilities; an application could call such a component, providing the image to compress, and the component could perform the desired operation and return the compressed image to the application. The Component Manager provides access to components and manages them by, for example, keeping track of the currently available components and routing requests to the appropriate component.

Functions by Task

Finding Components

Opening and Closing Components

Getting Information About Components

Retrieving Component Errors

Calling Component Functions

Accessing the Thread Safety Mode

Creating and Managing Universal Procedure Pointers

Registering Components

Dispatching to Component Functions

Managing Component Connections

Setting Component Errors

Working With Component Reference Constants

Accessing a Component’s Resource File

Calling Other Components

Capturing Components

Changing the Default Search Order

Functions

CallComponentCanDo

ComponentResult CallComponentCanDo (
   ComponentInstance ci,
   SInt16 ftnNumber
);

Parameters
ci
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentClose

ComponentResult CallComponentClose (
   ComponentInstance ci,
   ComponentInstance self
);

Parameters
ci
self
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentDispatch

ComponentResult CallComponentDispatch (
   ComponentParameters *cp
);

Parameters
cp
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentFunction

Invokes the specified function of your component.

ComponentResult CallComponentFunction (
   ComponentParameters *params,
   ComponentFunctionUPP func
);

Parameters
params

A pointer to the ComponentDescription structure that your component received from the Component Manager. These are the parameters originally provided by the application that called your component.

func

A universal procedure pointer to the component function that is to handle the request. The Component Manager calls the function referred to by the func parameter, using Pascal calling conventions, with the parameters that were originally provided by the application that called your component. The function referred to by this parameter must return a function result of type ComponentResult indicating the success or failure of the operation. See the ComponentRoutineProcPtr callback for more information on component functions.

Return Value

The value that is returned by the function referred to by the func parameter. Your component should use this value to set the current error for this connection. You can use the SetComponentInstanceError function to set the current error.

Discussion

When an application requests service from your component, your component receives a component parameters structure containing the parameters that the application provided when it called your component. Your component can use this structure to access the parameters directly. Alternatively, you can use either this function or CallComponentFunctionWithStorage to extract those parameters and pass them to a subroutine of your component. By taking advantage of these functions, you can simplify the structure of your component code.

If your component subroutine does not need global data, your component should use this function. If your component subroutine requires memory in which to store global data for the component, your component must use CallComponentFunctionWithStorage.

Availability
Declared In
Components.h

CallComponentFunctionWithStorage

Invokes the specified function of your component. 

ComponentResult CallComponentFunctionWithStorage (
   Handle storage,
   ComponentParameters *params,
   ComponentFunctionUPP func
);

Parameters
storage

A handle to the memory associated with the current connection. The Component Manager provides this handle to your component along with the request.

params

A pointer to the ComponentParameters structure that your component received from the Component Manager. These are the parameters originally provided by the application that called your component.

func

A universal procedure pointer to the component function that is to handle the request. The Component Manager calls the function referred to by the func parameter, using Pascal calling conventions, with the parameters that were originally provided by the application that called your component. These parameters are preceded by a handle to the memory associated with the current connection. The function referred to by the func parameter must return a function result of type ComponentResult indicating the success or failure of the operation. See the ComponentRoutineProcPtr callback for more information on component functions.

Return Value

The value that is returned by the function referred to by the func parameter. Your component should use this value to set the current error for this connection. Use the SetComponentInstanceError function to set the current error for a connection.

Discussion

When an application requests service from your component, your component receives a component parameters structure containing the parameters that the application provided when it called your component. Your component can use this structure to access the parameters directly. Alternatively, you can use either the CallComponentFunction function or this function to extract those parameters and pass them to a subroutine of your component. By taking advantage of these functions, you can simplify the structure of your component code.

If your component subroutine requires a handle to the memory associated with the connection, you must use this function. You allocate the memory for a given connection each time your component is opened. You inform the Component Manager that a connection has memory associated with it by calling the SetComponentInstanceError function.

Subroutines of a component that don’t need global data should use CallComponentFunction instead.

Availability
Declared In
Components.h

CallComponentFunctionWithStorageProcInfo

ComponentResult CallComponentFunctionWithStorageProcInfo (
   Handle storage,
   ComponentParameters *params,
   ProcPtr func,
   ProcInfoType funcProcInfo
);

Parameters
storage
params
funcProcInfo
Availability
Declared In
Components.h

CallComponentGetMPWorkFunction

ComponentResult CallComponentGetMPWorkFunction (
   ComponentInstance ci,
   ComponentMPWorkFunctionUPP *workFunction,
   void **refCon
);

Parameters
ci
workFunction
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentGetPublicResource

ComponentResult CallComponentGetPublicResource (
   ComponentInstance ci,
   OSType resourceType,
   SInt16 resourceID,
   Handle *resource
);

Parameters
ci
resourceType
resource
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentOpen

ComponentResult CallComponentOpen (
   ComponentInstance ci,
   ComponentInstance self
);

Parameters
ci
self
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentRegister

ComponentResult CallComponentRegister (
   ComponentInstance ci
);

Parameters
ci
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentTarget

ComponentResult CallComponentTarget (
   ComponentInstance ci,
   ComponentInstance target
);

Parameters
ci
target
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentUnregister

ComponentResult CallComponentUnregister (
   ComponentInstance ci
);

Parameters
ci
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CallComponentVersion

ComponentResult CallComponentVersion (
   ComponentInstance ci
);

Parameters
ci
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

CaptureComponent

Allows your component to capture another component. 

Component CaptureComponent (
   Component capturedComponent,
   Component capturingComponent
);

Parameters
capturedComponent

The component to be captured. Your component can obtain this identifier from the FindNextComponent function or from the component registration functions. You can use a component instance here, but you must coerce the data type appropriately.

capturingComponent

Your component. Note that you can use the component instance (appropriately coerced) that your component received in its open request in this parameter.

Return Value

A new component identifier. Your component can use this new identifier to refer to the captured component. For example, your component can open the captured component by providing this identifier to the OpenComponent structure. Your component must provide this identifier to the UncaptureComponent function to specify the component to be restored to the search list. If the component you wish to capture is already captured, the component identifier is set to NULL. See the description of the Component data type.

Discussion

Typically, your component captures another component when you want to override all or some of the features provided by a component or to provide new features. For example, a component called NewMath might capture a component called OldMath. Suppose the NewMath component provides a new function, DoExponent. Whenever NewMath gets an exponent request, it can handle the request itself. For all other requests, NewMath might call the OldMath component to perform the request.

After capturing a component, your component might choose to target a particular instance of the captured component.

In response to this function, the Component Manager removes the specified component from the list of available components. As a result, applications cannot retrieve information about the captured component or gain access to it. Current clients of the captured component are not affected by this function.

Availability
Declared In
Components.h

CloseComponent

Terminates your application’s connection to a component. 

OSErr CloseComponent (
   ComponentInstance aComponentInstance
);

Parameters
aComponentInstance

The connection you wish to close. Your application obtains the component instance from the OpenComponent function or the OpenDefaultComponent function. You can use a component identifier here, but you must coerce the data type appropriately.

Return Value

A result code. See “Component Manager Result Codes.”

Discussion

This function closes only a single connection. If your application has several connections to a single component, you must call it once for each connection.

Availability
Related Sample Code
Declared In
Components.h

CloseComponentResFile

Closes the resource file that your component opened previously with the OpenComponentResFile function. 

OSErr CloseComponentResFile (
   ResFileRefNum refnum
);

Parameters
refnum

The reference number that identifies the resource file to be closed. Your component obtains this value from the OpenComponentResFile function. Your component must close any open resource files before returning to the calling application.

Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

CountComponentInstances

Determines the number of open connections being managed by a specified component. 

long CountComponentInstances (
   Component aComponent
);

Parameters
aComponent

The component for which you want a count of open connections. You can use a component instance here, but you must coerce the data type appropriately.

Return Value

The number of open connections for the specified component.

Discussion

This function can be useful if you want to restrict the number of connections for your component or if your component needs to perform special processing based on the number of open connections.

Availability
Related Sample Code
Declared In
Components.h

CountComponents

Returns the number of registered components that meet the selection criteria specified by your application. 

long CountComponents (
   ComponentDescription *looking
);

Parameters
looking

A pointer to a ComponentDescription structure. Your application specifies the criteria for the component search in the fields of this structure.

The Component Manager ignores fields in the component description structure that are set to 0. For example, if you set all the fields to 0, the Component Manager returns the number of components registered in the system. Similarly, if you set all fields to 0 except for the componentManufacturer field, the Component Manager returns the number of registered components supplied by the manufacturer you specify.

Return Value

The number of components that meet the specified search criteria.

Availability
Declared In
Components.h

CSGetComponentsThreadMode

Indicates whether using thread-unsafe components is allowed in the current thread. 

CSComponentsThreadMode CSGetComponentsThreadMode (
   void
);

Return Value

A flag that indicates whether using thread-unsafe components is allowed in the current thread.

Availability
Declared In
Components.h

CSSetComponentsThreadMode

Sets whether or not using thread-unsafe components is allowed in the current thread. 

void CSSetComponentsThreadMode (
   CSComponentsThreadMode mode
);

Parameters
mode

A flag that determines whether the current thread is restricted to calling components that are thread-safe. You should set this flag to kCSAcceptThreadSafeComponentsOnlyMode whenever you want the current thread to call only components that are thread-safe.

Discussion

Core Services maintains a component thread-mode flag for each thread in the current process. The default value of this flag is kCSAcceptAllComponentsMode, which means the thread can call any component regardless of whether the component is thread-safe. Applications and other high-level code that call component-based APIs (such as QuickTime) from preemptive threads should call this function from their thread beforehand and pass in the value kCSAcceptThreadSafeComponentsOnlyMode.

A thread’s component thread-mode flag can safely retain its default value only if the thread is the main thread or if it participates in cooperative locking, such as Carbon Thread Manager-style cooperative threads and application threads that perform their own private locking.

Availability
Declared In
Components.h

DelegateComponentCall

Allows your component to pass on a request to a specified component. 

ComponentResult DelegateComponentCall (
   ComponentParameters *originalParams,
   ComponentInstance ci
);

Parameters
originalParams

A pointer to the ComponentParameters structure provided to your component by the Component Manager.

ci

The component instance that is to process the request. The Component Manager provides a component instance to your component when it opens a connection to another component with the OpenComponent or OpenDefaultComponent function. You must specify a component instance; this function does not accept a component identifier.

Return Value

The component result returned by the specified component.

Discussion

Your component may supplement its capabilities by using the services of another component to directly satisfy application requests using this function. For example, you might want to create two similar components that provide different levels of service to applications. Rather than completely implementing both components, you could design one to rely on the capabilities of the other. In this manner, you have to implement only that portion of the more capable component that provides additional services.

You may also invoke the services of another component using the standard mechanisms used by applications. The Component Manager then passes the requests to the appropriate component, and your component receives the results of those requests.

Your component must open a connection to the component to which the requests are to be passed. Your component must close that connection when it has finished using the services of the other component.

Your component should never use this function with open or close requests from the Component Manager—always use the OpenComponent and CloseComponent functions to manage connections with other components.

Availability
Declared In
Components.h

DisposeComponentFunctionUPP

void DisposeComponentFunctionUPP (
   ComponentFunctionUPP userUPP
);

Parameters
userUPP
Availability
Declared In
Components.h

DisposeComponentMPWorkFunctionUPP

void DisposeComponentMPWorkFunctionUPP (
   ComponentMPWorkFunctionUPP userUPP
);

Parameters
userUPP
Availability
Declared In
Components.h

DisposeComponentRoutineUPP

Disposes of the universal procedure pointer (UPP) to a component routine callback function.

void DisposeComponentRoutineUPP (
   ComponentRoutineUPP userUPP
);

Parameters
userUPP
Discussion

See the ComponentRoutineProcPtr callback for more information.

Availability
Declared In
Components.h

DisposeGetMissingComponentResourceUPP

void DisposeGetMissingComponentResourceUPP (
   GetMissingComponentResourceUPP userUPP
);

Parameters
userUPP
Availability
Declared In
Components.h

FindNextComponent

Returns the component identifier for the next registered component that meets the selection criteria specified by your application. 

Component FindNextComponent (
   Component aComponent,
   ComponentDescription *looking
);

Parameters
aComponent

The starting point for the search. Set this field to 0 to start the search at the beginning of the component list. If you are continuing a search, you can specify a component identifier previously returned by this function. The function then searches the remaining components.

looking

A pointer to a ComponentDescription structure. Your application specifies the criteria for the component search in the fields of this structure.

The Component Manager ignores fields in the component description structure that are set to 0. For example, if you set all the fields to 0, all components meet the search criteria. In this case, your application can retrieve information about all of the components that are registered in the system by repeatedly calling FindNextComponent and GetComponentInfo until the search is complete. Similarly, if you set all fields to 0 except for the componentManufacturer field, the Component Manager searches all registered components for a component supplied by the manufacturer you specify. Note that this function does not modify the contents of the component description structure you supply. To retrieve detailed information about a component, you need to use the GetComponentInfo function to get the component description structure for each returned component.

Return Value

The component identifier of a component that meets the search criteria or 0 when there are no more matching components. Your application can use the component identifier returned by this function to get more information about the component, using GetComponentInfo, or to open the component, using either the OpenDefaultComponent function or the OpenComponent function. See the description of the Component data type.

Availability
Related Sample Code
Declared In
Components.h

GetComponentIconSuite

Returns a handle to a component’s icon suite to your application.

OSErr GetComponentIconSuite (
   Component aComponent,
   Handle *iconSuite
);

Parameters
aComponent

The component whose icon suite you wish to obtain. Your application obtains a component identifier from the FindNextComponent function. If your application registers a component, it can also obtain a component identifier from the RegisterComponent or RegisterComponentResource function. You can use a component instance here, but you must coerce the data type appropriately.

iconSuite

On return, a pointer to a handle for the component’s icon suite or, if the component has not provided an icon suite, NULL. A component provides the resource ID of its icon family to the Component Manager in the optional extensions to the component resource. Your application is responsible for disposing of the returned icon suite handle.

Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

GetComponentIndString

OSErr GetComponentIndString (
   Component aComponent,
   Str255 theString,
   SInt16 strListID,
   SInt16 index
);

Parameters
aComponent
theString
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Related Sample Code
Declared In
Components.h

GetComponentInfo

Returns to your application the registration information for a component. 

OSErr GetComponentInfo (
   Component aComponent,
   ComponentDescription *cd,
   Handle componentName,
   Handle componentInfo,
   Handle componentIcon
);

Parameters
aComponent

The component about which you wish to obtain information. Your application obtains a component identifier from the FindNextComponent function. If your application registers a component, it can also obtain a component identifier from the RegisterComponent or RegisterComponentResource function.

You may supply a component instance rather than a component identifier to this function, but you must coerce the data type appropriately. Your application can obtain a component instance from the OpenComponent or OpenDefaultComponent functions.

cd

A pointer to a ComponentDescription structure. The function returns information about the specified component in this structure.

componentName

On return, a handle to the component’s name. If the component does not have a name, an empty handle. Set this field to NULL if you do not want to receive the component’s name.

componentInfo

On return, a handle to the component’s information string. If the component does not have an information string, an empty handle. Set this field to NULL if you do not want to receive the component’s information string.

componentIcon

On return, a handle to the component’s icon. If the component does not have an icon, an empty handle. Set this field to NULL if you do not want to receive the component’s icon. To get a handle to the component’s icon suite, if it provides one, use the GetComponentIconSuite function.

Return Value

A result code. See “Component Manager Result Codes.”

Discussion

For information on registering components, see “Registering Components”.

Availability
Related Sample Code
Declared In
Components.h

GetComponentInstanceError

Returns to your application the last error generated by a specific connection to a component.

OSErr GetComponentInstanceError (
   ComponentInstance aComponentInstance
);

Parameters
aComponentInstance

The component instance from which you want error information. Your application obtains the component instance from the OpenDefaultComponent function or the OpenComponent function. You can use a component identifier here, but you must coerce the data type appropriately.

Return Value

A result code. See “Component Manager Result Codes.”

Discussion

Some component functions return error information as their function result. Other component functions set an error code that your application can retrieve using this function. Refer to the documentation supplied with the component for information on how that particular component handles errors.

Once you have retrieved an error code, the Component Manager clears the error code for the connection. If you want to retain that error value, you should save it in your application’s local storage.

Availability
Declared In
Components.h

GetComponentInstanceStorage

Allows your component to retrieve a handle to the memory associated with a connection. 

Handle GetComponentInstanceStorage (
   ComponentInstance aComponentInstance
);

Parameters
aComponentInstance

The connection for which to retrieve the associated memory. The Component Manager provides a component instance to your component when the connection is opened. You can use a component identifier here, but you must coerce the data type appropriately.

Return Value

A handle to the memory associated with the specified connection.

Discussion

Typically, your component does not need to use this function, because the Component Manager provides this handle to your component each time the client application requests service from this connection.

Your component tells the Component Manager about the memory associated with a connection by calling the SetComponentInstanceStorage function.

Availability
Declared In
Components.h

GetComponentListModSeed

Allows your application to determine if the list of registered components has changed. 

SInt32 GetComponentListModSeed (
   void
);

Parameters
Return Value

The component registration seed number. Each time the Component Manager registers or unregisters a component it generates a new, unique seed number. By comparing the return value to values previously returned by this function, you can determine whether the list has changed. Your application may use this information to rebuild its internal component lists or to trigger other activity that is necessary whenever new components are available.

Availability
Declared In
Components.h

GetComponentPublicIndString

OSErr GetComponentPublicIndString (
   Component aComponent,
   Str255 theString,
   SInt16 strListID,
   SInt16 index
);

Parameters
aComponent
theString
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

GetComponentPublicResource

OSErr GetComponentPublicResource (
   Component aComponent,
   OSType resourceType,
   SInt16 resourceID,
   Handle *theResource
);

Parameters
aComponent
resourceType
theResource
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

GetComponentPublicResourceList

OSErr GetComponentPublicResourceList (
   OSType resourceType,
   SInt16 resourceID,
   SInt32 flags,
   ComponentDescription *cd,
   GetMissingComponentResourceUPP missingProc,
   void *refCon,
   void *atomContainerPtr
);

Parameters
resourceType
cd
missingProc
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

GetComponentRefcon

Retrieves the value of the reference constant for your component. 

long GetComponentRefcon (
   Component aComponent
);

Parameters
aComponent

The component whose reference constant you wish to get. You can use a component instance here, but you must coerce the data type appropriately.

Return Value

The reference constant for the specified component.

Discussion

There is one reference constant for each component, regardless of the number of connections to that component. When your component is registered, the Component Manager sets this reference constant to 0.

The reference constant is a 4-byte value that your component can use in any way you decide. For example, you might use the reference constant to store the address of a data structure that is shared by all connections maintained by your component. You should allocate shared structures in the system heap. Your component should deallocate the structure when its last connection is closed or when it is unregistered.

Availability
Declared In
Components.h

GetComponentResource

OSErr GetComponentResource (
   Component aComponent,
   OSType resType,
   SInt16 resID,
   Handle *theResource
);

Parameters
aComponent
resType
theResource
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

GetComponentTypeModSeed

SInt32 GetComponentTypeModSeed (
   OSType componentType
);

Parameters
componentType
Availability
Declared In
Components.h

InvokeComponentMPWorkFunctionUPP

ComponentResult InvokeComponentMPWorkFunctionUPP (
   void *globalRefCon,
   ComponentMPWorkFunctionHeaderRecordPtr header,
   ComponentMPWorkFunctionUPP userUPP
);

Parameters
header
userUPP
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

InvokeComponentRoutineUPP

Calls your component routine callback function

ComponentResult InvokeComponentRoutineUPP (
   ComponentParameters *cp,
   Handle componentStorage,
   ComponentRoutineUPP userUPP
);

Parameters
cp
componentStorage
userUPP
Return Value

See the description of the ComponentResult data type.

Discussion

See the ComponentRoutineProcPtr callback for more information.

Availability
Declared In
Components.h

InvokeGetMissingComponentResourceUPP

OSErr InvokeGetMissingComponentResourceUPP (
   Component c,
   OSType resType,
   SInt16 resID,
   void *refCon,
   Handle *resource,
   GetMissingComponentResourceUPP userUPP
);

Parameters
c
resType
resource
userUPP
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

NewComponentFunctionUPP

ComponentFunctionUPP NewComponentFunctionUPP (
   ProcPtr userRoutine,
   ProcInfoType procInfo
);

Parameters
procInfo
Return Value

See the description of the ComponentFunctionUPP data type.

Availability
Declared In
Components.h

NewComponentMPWorkFunctionUPP

ComponentMPWorkFunctionUPP NewComponentMPWorkFunctionUPP (
   ComponentMPWorkFunctionProcPtr userRoutine
);

Parameters
userRoutine
Return Value

See the description of the ComponentMPWorkFunctionUPP data type.

Availability
Declared In
Components.h

NewComponentRoutineUPP

Creates a new universal procedure pointer (UPP) to a component routine callback function.

ComponentRoutineUPP NewComponentRoutineUPP (
   ComponentRoutineProcPtr userRoutine
);

Parameters
userRoutine
Return Value

See the description of the ComponentRoutineUPP data type.

Discussion

See the ComponentRoutineProcPtr callback for more information.

Availability
Declared In
Components.h

NewGetMissingComponentResourceUPP

GetMissingComponentResourceUPP NewGetMissingComponentResourceUPP (
   GetMissingComponentResourceProcPtr userRoutine
);

Parameters
userRoutine
Return Value

See the description of the GetMissingComponentResourceUPP data type.

Availability
Declared In
Components.h

OpenAComponent

OSErr OpenAComponent (
   Component aComponent,
   ComponentInstance *ci
);

Parameters
aComponent
ci
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

OpenAComponentResFile

OSErr OpenAComponentResFile (
   Component aComponent,
   ResFileRefNum *resRef
);

Parameters
aComponent
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

OpenADefaultComponent

OSErr OpenADefaultComponent (
   OSType componentType,
   OSType componentSubType,
   ComponentInstance *ci
);

Parameters
componentType
componentSubType
ci
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Related Sample Code
Declared In
Components.h

OpenComponent

Opens a connection to the component with the component identifier specified by your application.

ComponentInstance OpenComponent (
   Component aComponent
);

Parameters
aComponent

The component you wish to open. Your application obtains this identifier from the FindNextComponent function. If your application registers a component, it can also obtain a component identifier from the RegisterComponent function or the RegisterComponentResource function.

Return Value

A component instance which identifies your application’s connection to the component. You must supply this component instance whenever you call the functions provided by the component. When you close the component, you must also supply this component instance to the CloseComponent function.

If it cannot open the specified component, the function returns NULL.

See the description of the ComponentInstance data type.

Discussion

Your application must open a component before it can call any component functions. To use this function, you must already have obtained a component identifier. Alternatively, you can use the OpenDefaultComponent function to open a component without calling FindNextComponent.

Note that your application may maintain several connections to a single component, or it may have connections to several components at the same time.

Availability
Related Sample Code
Declared In
Components.h

OpenComponentResFile

Allows your component to gain access to its resource file. 

ResFileRefNum OpenComponentResFile (
   Component aComponent
);

Parameters
aComponent

The component whose resource file you wish to open. Applications that register components may obtain this identifier from the RegisterComponentResource function. You can use a component instance here, but you must coerce the data type appropriately.

Return Value

A reference number that your component can use to read data from the appropriate resource file. If the specified component does not have an associated resource file or if the Component Manager cannot open the resource file, the function returns 0 or a negative number.

Discussion

This function opens the resource file with read-only permission. The Component Manager adds the resource file to the current resource chain. Your component must close the resource file with the CloseComponentResFile function before returning to the calling application. Note that there is only one resource file associated with a component.

Your component can use FSpOpenResFile or equivalent Resource Manager functions to open other resource files, but you must use this function to open your component’s resource file.

If you store your component in a component resource but register the component with the RegisterComponent function, rather than with the RegisterComponentResource or RegisterComponentResourceFile function, your component cannot access its resource file with this function.

Note that when working with resources, your component should always first save the current resource file, perform any resource operations, then restore the current resource file to its previous value before returning.

Availability
Declared In
Components.h

OpenDefaultComponent

Opens a connection to a registered component of the component type and subtype specified by your application. 

ComponentInstance OpenDefaultComponent (
   OSType componentType,
   OSType componentSubType
);

Parameters
componentType

The type of the component. All components of a particular type support a common set of interface functions. Use this parameter to search for components of a given type.

componentSubType

The subtype of the component. Different subtypes of a component type may support additional features or provide interfaces that extend beyond the standard functions for a given component type. For example, the subtype of an image compressor component indicates the compression algorithm employed by the compressor.

Your application can use the componentSubType parameter to perform a more specific lookup operation than is possible using only the componentType parameter. For example, you may want your application to use only components of a certain component type ('draw') that also have a specific subtype ('oval'). Set this parameter to 0 to select a component with any subtype value.

Return Value

A component instance that identifies the connection opened to the component which matches your search criteria. You must supply this component instance whenever you call the functions provided by the component. When you close the component, you must also supply this component instance to the CloseComponent function.

If more than one component in the list of registered components meets the search criteria, the function opens the first one that it finds in its list. If it cannot open the specified component, it returns NULL.

See the description of the ComponentInstance data type.

Discussion

Your application must open a component before it can call any component functions. This function searches for a component by type and subtype. You do not have to supply a component description structure or call the FindNextComponent function to use this function. If you want to exert more control over the selection process, you can use the FindNextComponent and OpenComponent functions.

Availability
Declared In
Components.h

RegisterComponent

Registers a component stored in memory.

Component RegisterComponent (
   ComponentDescription *cd,
   ComponentRoutineUPP componentEntryPoint,
   SInt16 global,
   Handle componentName,
   Handle componentInfo,
   Handle componentIcon
);

Parameters
cd

A pointer to a ComponentDescription structure that describes the component to be registered. You must correctly fill in the fields of this structure before calling this function. When applications search for components using the FindNextComponent function, the Component Manager compares the attributes you specify here with those specified by the application. If the attributes match, the Component Manager returns the component identifier to the application.

componentEntryPoint

A universal procedure pointer (UPP) to your component’s main entry point. The function referred to by this parameter receives all requests for the component. See the ComponentRoutineProcPtr callback for more information on creating a component function.

global

A set of flags that control the scope of component registration. See Register Component Resource flags for a description of the flags.

componentName

A handle to the component’s name. Set this parameter to NULL if you do not want to assign a name to the component.

componentInfo

A handle to the component’s information string. Set this parameter to NULL if you do not want to assign an information string to the component.

componentIcon

A handle to the component’s icon (a 32-by-32 pixel black-and-white icon). Set this parameter to NULL if you do not want to supply an icon for this component. Note that this icon is not used by the Finder you supply an icon only so that other components or applications can display your component’s icon if needed.

Return Value

The unique component identifier assigned to the component by the Component Manager or, if it cannot register the component, NULL. See the description of the Component data type.

Discussion

Before a component can be used by an application, the component must be registered with the Component Manager. Applications can then find and open the component using the standard Component Manager functions.

Components you register with the RegisterComponent function must be in memory when you call this function. If you want to register a component that is stored in the resource fork of a file, use the RegisterComponentResource function. Use the RegisterComponentResourceFile function to register all components in the resource fork of a file. The Component Manager automatically registers component resources stored in files with file types of 'thng' that are stored in the Extensions folder. See “Resources” for more information on component resource files.

Note that a component residing in your application heap remains registered until your application unregisters it or quits. When an application quits, the Component Manager automatically closes any component connections to that application. In addition, if the application has registered components that reside in its heap space, the Component Manager automatically unregisters those components. A component residing in the system heap and registered by your application remains registered until your application unregisters it or until the computer is shut down.

Availability
Declared In
Components.h

RegisterComponentFileRef

OSErr RegisterComponentFileRef (
   const FSRef *ref,
   SInt16 global
);

Parameters
ref
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

RegisterComponentFileRefEntries

OSErr RegisterComponentFileRefEntries (
   const FSRef *ref,
   SInt16 global,
   const ComponentDescription *toRegister,
   UInt32 registerCount
);

Parameters
ref
toRegister
registerCount
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

RegisterComponentResource

Registers a component stored in a resource file.

Component RegisterComponentResource (
   ComponentResourceHandle cr,
   SInt16 global
);

Parameters
cr

A handle to a component resource that describes the component to be registered. The component resource contains all the information required to register the component. Components you register with this function must be stored in a resource file as a component resource. The Component Manager automatically registers component resources stored in files with file types of 'thng' that are stored in the Extensions folder. See “Resources” for more information on component resource files.

global

A set of flags that controls the scope of component registration. See Register Component Resource flags for a description of the flags.

Return Value

The unique component identifier assigned to the component by the Component Manager, or NULL if the function could not register the component. See the description of the Component data type.

Discussion

Before a component can be used by an application, the component must be registered with the Component Manager. Applications can then find and open the component using the standard Component Manager functions.

If you want to register a component that is in memory, use the RegisterComponent function.

This function does not actually load the code specified by the component resource into memory. Rather, the Component Manager loads the component code the first time an application opens the component. If the code is not in the same file as the component resource or if the Component Manager cannot find the file, the open request fails.

Note that a component registered locally by your application remains registered until your application unregisters it or quits. When an application quits, the Component Manager automatically closes any component connections to that application. In addition, if the application has registered components that reside in its heap space, the Component Manager automatically unregisters those components. A component registered globally by your application remains registered until your application unregisters it or until the computer is shut down.

Availability
Declared In
Components.h

RegisterComponentResourceFile

Registers all component resources in the given resource file.

SInt32 RegisterComponentResourceFile (
   SInt16 resRefNum,
   SInt16 global
);

Parameters
resRefNum

The reference number of the resource file containing the components to register.

global

A set of flags that control the scope of the registration of the components in the resource file. See Register Component Resource flags for a description of the flags.

Return Value

The number of components registered, if all components in the specified resource file are successfully registered. If one or more of the components in the resource file could not be registered, or if the specified file reference number is invalid, a negative function result.

Discussion

Before a component can be used by an application, the component must be registered with the Component Manager. The Component Manager automatically registers component resources stored in files with file types of 'thng' that are stored in the Extensions folder. For a description of the format and content of component resources, see “Resources”.

Availability
Declared In
Components.h

ResolveComponentAlias

Component ResolveComponentAlias (
   Component aComponent
);

Parameters
aComponent
Return Value

See the description of the Component data type.

Availability
Declared In
Components.h

SetComponentInstanceError

Passes error information to the Component Manager which sets the current error value for the appropriate connection.

void SetComponentInstanceError (
   ComponentInstance aComponentInstance,
   OSErr theError
);

Parameters
aComponentInstance

The connection for which to set the error. The Component Manager provides a component instance to your component when the connection is opened. The Component Manager also provides a component instance to your component as the first parameter in the params field of the parameters structure.

theError

The new value for the current error.

Discussion

In general, your component returns error information in its function result a nonzero function result indicates an error occurred, and a function result of 0 indicates the request was successful. However, some requests require that your component return other information as its function result. In these cases, your component can use this function to report its latest error state to the Component Manager. You can also use this function at any time during your component’s execution to report an error.

Applications retrieve this error information by calling the GetComponentInstanceError function. The documentation for your component should specify how the component indicates errors.

Availability
Declared In
Components.h

SetComponentInstanceStorage

Allows your component to associate memory with a connection. 

void SetComponentInstanceStorage (
   ComponentInstance aComponentInstance,
   Handle theStorage
);

Parameters
aComponentInstance

The connection to associate with the allocated memory. The Component Manager provides a component instance to your component when the connection is opened. You can use a component identifier here, but you must coerce the data type appropriately.

theStorage

A handle to the memory that your component has allocated for the connection. Your component must allocate this memory in the current heap. The Component Manager saves this handle and provides it to your component, along with other parameters, in subsequent requests to this connection.

Discussion

When an application or component opens a connection to your component, the Component Manager sends your component an open request. In response to this open request, your component should set up an environment to service the connection. Typically, your component should allocate some memory for the connection. Your component can then use that memory to maintain state information appropriate to the connection.

Your component should dispose of any allocated memory for the connection only in response to the close request. Note that whenever an open request fails, the Component Manager always issues the close request. Furthermore, the value stored with this function is always passed to the close request, so it must be valid or NULL. If the open request tries to dispose of its allocated memory before returning, it should call this function again with a NULL handle to keep the Component Manager from passing an invalid handle to the close request.

Availability
Related Sample Code
Declared In
Components.h

SetComponentRefcon

Sets the reference constant for your component.

void SetComponentRefcon (
   Component aComponent,
   long theRefcon
);

Parameters
aComponent

The component whose reference constant you wish to set. You can use a component instance here, but you must coerce the data type appropriately.

theRefcon

The reference constant value that you want to set for your component. Your component can retrieve the reference constant using the GetComponentRefcon function.

Discussion

There is one reference constant for each component, regardless of the number of connections to that component. When your component is registered, the Component Manager sets this reference constant to 0.

The reference constant is a 4-byte value that your component can use in any way you decide. For example, you might use the reference constant to store the address of a data structure that is shared by all connections maintained by your component. You should allocate shared structures in the system heap. Your component should deallocate the structure when its last connection is closed or when it is unregistered.

Availability
Declared In
Components.h

SetDefaultComponent

Changes the search order for registered components. 

OSErr SetDefaultComponent (
   Component aComponent,
   SInt16 flags
);

Parameters
aComponent

The component which you wish moved to the front of the search chain. The order of the search chain influences which component the Component Manager selects in response to an application’s use of the OpenDefaultComponent and FindNextComponent functions. You can use a component instance here, but you must coerce the data type appropriately.

flags

A value specifying the control information governing the operation. The value of this parameter controls which component description fields the Component Manager examines during the reorder operation. Set the appropriate flags to 1 to define the fields that are examined during the reorder operation. See Set Default Component Flags for a description of the values you can use here.

Return Value

A result code. See “Component Manager Result Codes.”

Discussion

Note that this function changes the search order for all applications. As a result, you should use this function carefully.

Availability
Declared In
Components.h

UncaptureComponent

Allows your component to uncapture a previously captured component.

OSErr UncaptureComponent (
   Component aComponent
);

Parameters
aComponent

The component to be uncaptured. Your component obtains this identifier from the CaptureComponent function. You can use a component instance here, but you must coerce the data type appropriately.

Return Value

A result code. See “Component Manager Result Codes.”

Discussion

This function restores the specified component to the list of available components. Applications can then access the component and retrieve information about the component using Component Manager functions.

Availability
Declared In
Components.h

UnregisterComponent

Removes a component from the Component Manager’s registration list.

OSErr UnregisterComponent (
   Component aComponent
);

Parameters
aComponent

The component to be removed. Applications that register components may obtain this identifier from the RegisterComponent or RegisterComponentResource functions. The component must not be in use by any applications or components. You can use a component instance here, but you must coerce the data type appropriately.

Return Value

A result code. See “Component Manager Result Codes.” If there are open connections to the component, returns a validInstancesExist error.

Discussion

Most components are registered at startup and remain registered until the computer is shut down. However, you may want to provide some services temporarily. In that case you dispose of the component that provides the temporary service by using this function.

Availability
Declared In
Components.h

Callbacks

ComponentMPWorkFunctionProcPtr

typedef ComponentResult (*ComponentMPWorkFunctionProcPtr) (
   void * globalRefCon,
   ComponentMPWorkFunctionHeaderRecordPtr header
);

If you name your function MyComponentMPWorkFunctionProc, you would declare it like this:

ComponentResult MyComponentMPWorkFunctionProc (
   void * globalRefCon,
   ComponentMPWorkFunctionHeaderRecordPtr header
);

Parameters
header
Return Value

See the description of the ComponentResult data type.

Availability
Declared In
Components.h

ComponentRoutineProcPtr

Defines a pointer to your component callback function, which serves as the main entry point into your component and performs the component’s services. 

typedef ComponentResult (*ComponentRoutineProcPtr) (
   ComponentParameters * cp,
   Handle componentStorage
);

If you name your function MyComponentRoutineProc, you would declare it like this:

ComponentResult ComponentRoutineProcPtr (
   ComponentParameters * cp,
   Handle componentStorage
);

Parameters
cp

A ComponentParameters structure. The what field of the component parameters structure indicates the action your component should perform. The parameters that the client invoked your function with are contained in the params field of the component parameters structure. Your component can use the CallComponentFunction or CallComponentFunctionWithStorage function to extract the parameters from this structure.

componentStorage

A handle to any memory that your component has associated with the connection. Typically, upon receiving an open request, your component allocates memory and uses the SetComponentInstanceStorage function to associate the allocated memory with the component connection.

Return Value

Your component should return a value of type ComponentResult. If your component does not return error information as its function result, it should indicate errors using the SetComponentInstanceError function. See the description of the ComponentResult data type.

Discussion

You pass a pointer to your component callback function to the Component Manager when you register your component. The Component Manager can then call your component when another application or component requests its services. When your component receives a request, it should perform the action specified in the what field of the component parameters structure.

The pointer which you pass to the Component Manager should be a universal procedure pointer (UPP). The definition of the UPP data type for your component function is as follows:

typedef (ComponentRoutineProcPtr) ComponentRoutineUPP;

Before using your component function, you must first create a UPP for your callback function, using the NewComponentRoutineUPP function, as shown here:

ComponentRoutineUPP MyComponentRoutineUPP;
MyComponentRoutineUPP =             NewComponentRoutineUPP(&MyComponentRoutineProc)

You then pass MyComponentRoutineUPP to the Component Manager when you register your component. The Component Manager will call your function each time your component receives a request. If you wish to call your component function yourself, you can use the InvokeComponentRoutineUPP function.

result = InvokeComponentRoutineUPP &myParams, myStorage,              MyComponentRoutineUPP)

When you are finished with your component callback function, you should dispose of the universal procedure pointer associated with it, using the DisposeComponentRoutineUPP function.

DisposeComponentRoutineUPP(MyComponentRoutineUPP);

To provide a component, you define a component function and supply the appropriate registration information. You store your component function in a code resource and typically store your component’s registration information as resources in a component file.

Availability
Declared In
Components.h

GetMissingComponentResourceProcPtr

typedef OSErr (*GetMissingComponentResourceProcPtr) (
   Component c,
   OSType resType,
   short resID,
   void * refCon,
   Handle * resource
);

If you name your function MyGetMissingComponentResourceProc, you would declare it like this:

OSErr GetMissingComponentResourceProcPtr (
   Component c,
   OSType resType,
   short resID,
   void * refCon,
   Handle * resource
);

Parameters
c
resType
resource
Return Value

A result code. See “Component Manager Result Codes.”

Availability
Declared In
Components.h

Data Types

ComponentAliasResource

struct ComponentAliasResource {
   ComponentResource cr;
   ComponentDescription aliasCD;
};
typedef struct ComponentAliasResource ComponentAliasResource;

Fields
cr
aliasCD
Availability
Declared In
Components.h

ComponentDependencyArray

struct ComponentDependencyArray {
   SInt32 count;
   ComponentDescription descArray[1];
};

Fields
count
descArray

ComponentDescription

struct ComponentDescription {
   OSType componentType;
   OSType componentSubType;
   OSType componentManufacturer;
   unsigned long componentFlags;
   unsigned long componentFlagsMask;
};
typedef struct ComponentDescription ComponentDescription;

Fields
componentType

A four-character code that identifies the type of component. All components of a particular type must support a common set of interface functions. For example, drawing components all have a component type of 'draw'.

If you are developing an application which uses components, you can use this field to search for components of a given type by specifying the component type in this field of the component description structure you supply to the FindNextComponent function or the CountComponents function. A value of 0 operates as a wildcard.

If you are developing a component, it must support all of the standard functions for the component type specified by this field. Type codes with all lowercase characters are reserved for definition by Apple. You can define your own component type code as long as you register it with Apple’s Component Registry Group.

componentSubType

A four-character code that identifies the subtype of the component. Different subtypes of a component type may support additional features or provide interfaces that extend beyond the standard functions for a given component type. For example, the subtype of drawing components indicates the type of object the component draws. Drawing components that draw ovals have a subtype of 'oval'.

If you are developing an application which uses components, you can use the componentSubType field to perform a more specific lookup operation than is possible using only the componentType field. By specifying particular values for both fields in the component description structure that you supply to the FindNextComponent or CountComponents function, your application retrieves information about only those components that meet both of these search criteria. A value of 0 operates as a wildcard.

If you are developing a component, you may use this field to indicate more specific information about the capabilities of the component. There are no restrictions on the content you assign to this field. If no additional information is appropriate for your component type, you may set the componentSubType field to 0.

componentManufacturer

A four-character code that identifies the manufacturer of the component. This field allows for further differentiation between individual components. For example, components made by a specific manufacturer may support an extended feature set. Components provided by Apple use a manufacturer value of 'appl'.

If you are developing an application which uses components, you can use this field to find components from a certain manufacturer. Specify the appropriate manufacturer code in this field of the component description structure you supply to the FindNextComponent or CountComponents function. A value of 0 operates as a wildcard.

If you are developing a component, you obtain your manufacturer code, which can be the same as your application signature, from Apple’s Component Registry Group.

componentFlags

A 32-bit field that provides additional information about a particular component.

The high-order 8 bits are reserved for definition by the Component Manager. If you are developing an application, you should usually set these bits to 0.

The low-order 24 bits are specific to each component type. These flags can be used to indicate the presence of features or capabilities in a given component.

If you are developing an application which uses components, you can use these flags to further narrow the search criteria applied by the FindNextComponent or CountComponents function. If you use the componentFlags field in a component search, you use the componentFlagsMask field to indicate which flags are to be considered in the search.

If you are developing a component, you can use these flags to indicate any special capabilities or features of your component. You may use all 24 bits, as appropriate to its component type. You must set all unused bits to 0.

componentFlagsMask

A 32-bit field that indicates which flags in the componentFlags field are relevant to a particular component search operation.

If you are developing an application which uses components, your application should set each bit which corresponds to a flag in the componentFlags field that is to be considered as a search criterion by the FindNextComponent or CountComponents function to 1. The Component Manager considers only these flags during the search. You specify the desired flag value (either 0 or 1) in the componentFlags field.

For example, to look for a component with a specific control flag that is set to 0, set the appropriate bit in the ComponentFlags field to 0 and the same bit in the ComponentFlagsMask field to 1. To look for a component with a specific control flag that is set to 1, set the bit in the ComponentFlags field to 1 and the same bit in the ComponentFlagsMask field to 1. To ignore a flag, set the bit in the ComponentFlagsMask field to 0.

If you are developing a component, your component must set the componentFlagsMask field in its component description structure to 0.

Discussion

The ComponentDescription structure identifies the characteristics of a component, including the type of services offered by the component and its manufacturer.

Applications and components use component description structures in different ways. An application that uses components specifies the selection criteria for a component in a component description structure. The functions FindNextComponent , CountComponents , and GetComponentInfo all use the component description structure to specify the criteria for their search.

A component uses the component description structure to specify its registration information and capabilities and identify itself to the Component Manager. If your component is stored in a component resource, the information in the component description structure must be part of that resource. See the description of the component ‘thng’ resource. If you have developed an application that registers your component, that application must supply a component description structure to the RegisterComponent function. See “Registering Components” for information about registering components.

The ComponentDescription data type defines the component description structure. Note that the valid values of fields in the component description structure are determined by the component type specification. For example, all image compressor components must use the componentSubType field to specify the compression algorithm used by the compressor.

Availability
Declared In
Components.h

ComponentFunctionUPP

typedef UniversalProcPtr ComponentFunctionUPP;

Availability
Declared In
Components.h

ComponentInstanceRecord

struct ComponentInstanceRecord {
   long data[1];
};
typedef struct ComponentInstanceRecord ComponentInstanceRecord;
typedef ComponentInstanceRecord * ComponentInstance;

Fields
data
Availability
Declared In
Components.h

ComponentMPWorkFunctionHeaderRecord

struct ComponentMPWorkFunctionHeaderRecord {
   UInt32 headerSize;
   UInt32 recordSize;
   UInt32 workFlags;
   UInt16 processorCount;
   UInt8 unused;
   UInt8 isRunning;
};
typedef struct ComponentMPWorkFunctionHeaderRecord  ComponentMPWorkFunctionHeaderRecord;
typedef ComponentMPWorkFunctionHeaderRecord *  ComponentMPWorkFunctionHeaderRecordPtr;

Fields
headerSize
recordSize
workFlags
processorCount
unused
isRunning
Availability
Declared In
Components.h

ComponentMPWorkFunctionUPP

typedef ComponentMPWorkFunctionProcPtr ComponentMPWorkFunctionUPP;

Discussion

For more information, see the description of the ComponentMPWorkFunctionUPP callback function.

Availability
Declared In
Components.h

ComponentParameters

struct ComponentParameters {
   UInt8 flags;
   UInt8 paramSize;
   short what;
   long params[1];
};
typedef struct ComponentParameters ComponentParameters;

Fields
flags

Reserved for use by Apple.

paramSize

Specifies the number of bytes of parameter data for this request. The actual parameters are stored in the params field.

what

Specifies the type of request. Component designers define the meaning of positive values and assign them to requests that are supported by components of a given type. Negative values are reserved for definition by Apple. See “Result Codes” for Apple-defined request code values.

params

An array that contains the parameters specified by the application that called your component. You can use the CallComponentRoutine or CallComponentRoutineWithStorage function to convert this array into a Pascal-style invocation of a subroutine in your component.

Discussion

The Component Manager uses the component parameters structure to pass information to your component about a request from an application. Functions which use this data type are CallComponentFunction , CallComponentFunctionWithStorage , and DelegateComponentCall.The information in this structure completely defines the request. Your component services the request as appropriate.

The ComponentParameters data type defines the component parameters structure.

Availability
Declared In
Components.h

ComponentPlatformInfo

struct ComponentPlatformInfo {
   long componentFlags;
   ResourceSpec component;
   short platformType;
};
typedef struct ComponentPlatformInfo ComponentPlatformInfo;

Fields
component
Availability
Declared In
Components.h

ComponentPlatformInfoArray

struct ComponentPlatformInfoArray {
   long count;
   ComponentPlatformInfo platformArray[1];
};
typedef struct ComponentPlatformInfoArray ComponentPlatformInfoArray;

Fields
platformArray
Availability
Declared In
Components.h

ComponentRecord

struct ComponentRecord {
   long data[1];
};
typedef struct ComponentRecord ComponentRecord;
typedef ComponentRecord * Component;

Fields
data
Availability
Declared In
Components.h

ComponentResource

struct ComponentResource {
   ComponentDescription cd;
   ResourceSpec component;
   ResourceSpec componentName;
   ResourceSpec componentInfo;
   ResourceSpec componentIcon;
};
typedef struct ComponentResource ComponentResource;
typedef ComponentResource * ComponentResourcePtr;

Fields
cd

A ComponentDescription structure that specifies the characteristics of the component.

component

A resource specification structure that specifies the type and ID of the component code resource. The resType field of the resource specification structure may contain any value. The component’s main entry point must be at offset 0 in the resource.

componentName

A resource specification structure that specifies the resource type and ID for the name of the component. This is a Pascal string. Typically, the name is stored in a resource of type 'STR '.

componentInfo

A resource specification structure that specifies the resource type and ID for the information string that describes the component. This is a Pascal string. Typically, the information string is stored in a resource of type 'STR '. You might use the information stored in this resource in a Get Info dialog box.

componentIcon

A resource specification structure that specifies the resource type and ID for the icon for a component. Component icons are stored as 32-by-32 bit maps. Typically, the icon is stored in a resource of type 'ICON'. Note that this icon is not used by the Finder you supply an icon only so that other components or applications can display your component’s icon in a dialog box if needed.

Discussion

The ComponentResource data type defines the structure of a component resource. You can also optionally append to the end of this structure the information defined by the ComponentResourceExtension data type.

Availability
Declared In
Components.h

ComponentResourceExtension

struct ComponentResourceExtension {
   long componentVersion;
   long componentRegisterFlags;
   short componentIconFamily;
};
typedef struct ComponentResourceExtension ComponentResourceExtension;

Fields
componentVersion

The version number of the component. If you specify the componentDoAutoVersion flag in componentRegisterFlags, the Component Manager must obtain the version number of your component when your component is registered. Either you can provide a version number in your component’s resource, or you can specify a value of 0 for its version number. If you specify 0, the Component Manager sends your component a version request to get the version number of your component.

componentRegisterFlags

A set of flags containing additional registration information. See Component Resource Extension Flags for the flag values.

componentIconFamily

The resource ID of an icon family. You can provide an icon family in addition to the icon provided in the componentIcon field. Note that members of this icon family are not used by the Finder you supply an icon family only so that other components or applications can display your component’s icon in a dialog box if needed.

Discussion

You can optionally include in your component resource the information defined by the ComponentResourceExtension data type:

Availability
Declared In
Components.h

ComponentResult

typedef long ComponentResult;

Discussion

Availability
Declared In
Components.h

ComponentRoutineUPP

typedef ComponentRoutineProcPtr ComponentRoutineUPP;

Discussion

For more information, see the description of the ComponentRoutineUPP callback function.

Availability
Declared In
Components.h

ExtComponentResource

struct ExtComponentResource {
   ComponentDescription cd;
   ResourceSpec component;
   ResourceSpec componentName;
   ResourceSpec componentInfo;
   ResourceSpec componentIcon;
   long componentVersion;
   long componentRegisterFlags;
   short componentIconFamily;
   long count;
   ComponentPlatformInfo platformArray[1];
};
typedef struct ExtComponentResource ExtComponentResource;
typedef ExtComponentResource * ExtComponentResourcePtr;

Fields
cd
component
componentName
componentInfo
componentIcon
platformArray
Availability
Declared In
Components.h

GetMissingComponentResourceUPP

typedef GetMissingComponentResourceProcPtr GetMissingComponentResourceUPP;

Discussion

For more information, see the description of the GetMissingComponentResourceUPP callback function.

Availability
Declared In
Components.h

RegisteredComponentInstanceRecord

struct RegisteredComponentInstanceRecord {
   long data[1];
};
typedef struct RegisteredComponentInstanceRecord  RegisteredComponentInstanceRecord;
typedef RegisteredComponentInstanceRecord *  RegisteredComponentInstanceRecordPtr;

Fields
data
Availability
Declared In
Components.h

RegisteredComponentRecord

struct RegisteredComponentRecord {
   long data[1];
};
typedef struct RegisteredComponentRecord RegisteredComponentRecord;
typedef RegisteredComponentRecord * RegisteredComponentRecordPtr;

Fields
data
Availability
Declared In
Components.h

ResourceSpec

struct ResourceSpec {
   OSType resType;
   short resID;
};
typedef struct ResourceSpec ResourceSpec;

Fields
resType

The type of the resource.

resID

The ID of the resource.

Discussion

The ComponentResource structure uses the resource specification structure, defined by the ResourceSpec data type, to describe the component’s code, name, information string, or icon. The resources specified by the resource specification structures must reside in the same resource file as the component resource itself.

Availability
Declared In
Components.h

Constants

cmpAliasNoFlags

enum {
   cmpAliasNoFlags = 0,
   cmpAliasOnlyThisFile = 1
};

Constants
cmpAliasNoFlags

Available in Mac OS X v10.0 and later.

Declared in Components.h.

cmpAliasOnlyThisFile

Available in Mac OS X v10.0 and later.

Declared in Components.h.

cmpIsMissing

enum {
   cmpThreadSafe = 1L << 28,
   cmpIsMissing = 1L << 29,
   cmpWantsRegisterMessage = 1L << 31
};

Constants
cmpThreadSafe

Available in Mac OS X v10.3 and later.

Declared in Components.h.

cmpIsMissing

Available in Mac OS X v10.0 and later.

Declared in Components.h.

cmpWantsRegisterMessage

The setting of the cmpWantsRegisterMessage bit determines whether the Component Manager calls this component during registration. Set this bit to 1 if your component should be called when it is registered; otherwise, set this bit to 0.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

Discussion

These values are used by the componentFlags field of the ComponentDescription structure to provide additional information about a component.

Component Resource Extension Flags

enum {
   componentDoAutoVersion = (1 << 0),
   componentWantsUnregister = (1 << 1),
   componentAutoVersionIncludeFlags = (1 << 2),
   componentHasMultiplePlatforms = (1 << 3),
   componentLoadResident = (1 << 4)
};

Constants
componentDoAutoVersion

Specify this flag if you want the Component Manager to resolve conflicts between different versions of the same component. If you specify this flag, the Component Manager registers your component only if there is no later version available. If an older version is already registered, the Component Manager unregisters it. If a newer version of the same component is registered after yours, the Component Manager automatically unregisters your component. You can use this automatic version control feature to make sure that the most recent version of your component is registered, regardless of the number of versions that are installed

Available in Mac OS X v10.0 and later.

Declared in Components.h.

componentWantsUnregister

Specify this flag if you want your component to receive an unregister request when it is unregistered.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

componentAutoVersionIncludeFlags

Specify this flag if you want the Component Manager to include the componentFlags field of the component description structure when it searches for identical components in the process of performing automatic version control for your component. If you do not specify this flag, the Component Manager searches only the componentType, componentSubType, and componentManufacturer fields.

Note that the setting of the componentAutoVersionIncludeFlags flag affects automatic version control only and does not affect the search operations performed by FindNextComponent and CountComponents.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

componentHasMultiplePlatforms

Available in Mac OS X v10.0 and later.

Declared in Components.h.

componentLoadResident

Available in Mac OS X v10.0 and later.

Declared in Components.h.

Discussion

These values are used in the ComponentResourceExtension structure to specify additional information about component registration.

CSComponentsThreadMode

typedef UInt32 CSComponentsThreadMode;
enum {
   kCSAcceptAllComponentsMode = 0,
   kCSAcceptThreadSafeComponentsOnlyMode = 1
};

Constants
kCSAcceptAllComponentsMode

Available in Mac OS X v10.3 and later.

Declared in Components.h.

kCSAcceptThreadSafeComponentsOnlyMode

Available in Mac OS X v10.3 and later.

Declared in Components.h.

kAnyComponentType

enum {
   kAnyComponentType = 0,
   kAnyComponentSubType = 0,
   kAnyComponentManufacturer = 0,
   kAnyComponentFlagsMask = 0
};

Constants
kAnyComponentType

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kAnyComponentSubType

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kAnyComponentManufacturer

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kAnyComponentFlagsMask

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kAppleManufacturer

enum {
   kAppleManufacturer = 'appl',
   kComponentResourceType = 'thng',
   kComponentAliasResourceType = 'thga'
};

Constants
kAppleManufacturer

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentResourceType

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentAliasResourceType

Available in Mac OS X v10.0 and later.

Declared in Components.h.

mpWorkFlagDoWork

enum {
   mpWorkFlagDoWork = (1 << 0),
   mpWorkFlagDoCompletion = (1 << 1),
   mpWorkFlagCopyWorkBlock = (1 << 2),
   mpWorkFlagDontBlock = (1 << 3),
   mpWorkFlagGetProcessorCount = (1 << 4),
   mpWorkFlagGetIsRunning = (1 << 6)
};

Constants
mpWorkFlagDoWork

Available in Mac OS X v10.0 and later.

Declared in Components.h.

mpWorkFlagDoCompletion

Available in Mac OS X v10.0 and later.

Declared in Components.h.

mpWorkFlagCopyWorkBlock

Available in Mac OS X v10.0 and later.

Declared in Components.h.

mpWorkFlagDontBlock

Available in Mac OS X v10.0 and later.

Declared in Components.h.

mpWorkFlagGetProcessorCount

Available in Mac OS X v10.0 and later.

Declared in Components.h.

mpWorkFlagGetIsRunning

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platform68k

enum {
   platform68k = 1,
   platformPowerPC = 2,
   platformInterpreted = 3,
   platformWin32 = 4,
   platformPowerPCNativeEntryPoint = 5,
   platformIA32NativeEntryPoint = 6
};

Constants
platform68k

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformPowerPC

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformInterpreted

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformWin32

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformPowerPCNativeEntryPoint

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformIA32NativeEntryPoint

Available in Mac OS X v10.3 and later.

Declared in Components.h.

Discussion

platformIRIXmips

enum {
   platformIRIXmips = 1000,
   platformSunOSsparc = 1100,
   platformSunOSintel = 1101,
   platformLinuxppc = 1200,
   platformLinuxintel = 1201,
   platformAIXppc = 1300,
   platformNeXTIntel = 1400,
   platformNeXTppc = 1401,
   platformNeXTsparc = 1402,
   platformNeXT68k = 1403,
   platformMacOSx86 = 1500
};

Constants
platformIRIXmips

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformSunOSsparc

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformSunOSintel

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformLinuxppc

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformLinuxintel

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformAIXppc

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformNeXTIntel

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformNeXTppc

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformNeXTsparc

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformNeXT68k

Available in Mac OS X v10.0 and later.

Declared in Components.h.

platformMacOSx86

Available in Mac OS X v10.0 and later.

Declared in Components.h.

Register Component Resource flags

enum {
   registerComponentGlobal = 1,
   registerComponentNoDuplicates = 2,
   registerComponentAfterExisting = 4,
   registerComponentAliasesOnly = 8
};

Constants
registerComponentGlobal

Specify this flag to indicate that this component should be made available to other applications and clients as well as the one performing the registration. If you do not specify this flag, the component is available for use only by the registering application or component (that is, the component is local to the A5 world of the registering program).

Available in Mac OS X v10.0 and later.

Declared in Components.h.

registerComponentNoDuplicates

Specify this flag to indicate that if a component with identical characteristics to the one being registered already exists, then the new one should not be registered (RegisterComponent returns 0 in this situation). If you do not specify this flag, the component is registered even if a component with identical characteristics to the one being registered already exists.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

registerComponentAfterExisting

Specify this flag to indicate that this component should be registered after all other components with the same component type. Usually components are registered before others with identical descriptions; specifying this flag overrides that behavior.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

registerComponentAliasesOnly

Available in Mac OS X v10.0 and later.

Declared in Components.h.

Discussion

The functions RegisterComponent , RegisterComponentResource , and RegisterComponentResourceFile use these flags in the global parameter.

Request Codes

enum {
   kComponentOpenSelect = -1,
   kComponentCloseSelect = -2,
   kComponentCanDoSelect = -3,
   kComponentVersionSelect = -4,
   kComponentRegisterSelect = -5,
   kComponentTargetSelect = -6,
   kComponentUnregisterSelect = -7,
   kComponentGetMPWorkFunctionSelect = -8,
   kComponentExecuteWiredActionSelect = -9,
   kComponentGetPublicResourceSelect = -10
};

Constants
kComponentOpenSelect

A request to open a connection. Your component must respond to this request code.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentCloseSelect

A request to close a connection. Your component must respond to this request code.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentCanDoSelect

A request to determine whether your component supports a particular request. Your component must respond to this request code

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentVersionSelect

A request to return your component’s version number. Your component must respond to this request code.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentRegisterSelect

A request to determine whether your component can operate in the current environment. Your component may or may not respond to this request code.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentTargetSelect

A request to call another component whenever your component would call itself. Your component may or may not respond to this request code.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentUnregisterSelect

A request to perform any operations necessary as a result of your component being unregistered. Your component may or may not respond to this request code

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentGetMPWorkFunctionSelect

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentExecuteWiredActionSelect

Available in Mac OS X v10.0 and later.

Declared in Components.h.

kComponentGetPublicResourceSelect

Available in Mac OS X v10.0 and later.

Declared in Components.h.

Discussion

These values are used in the ComponentParameters structure to specify the type of a request to a component. Apple has defined these request codes:

Set Default Component Flags

enum {
   defaultComponentIdentical = 0,
   defaultComponentAnyFlags = 1,
   defaultComponentAnyManufacturer = 2,
   defaultComponentAnySubType = 4,
   defaultComponentAnyFlagsAnyManufacturer = (defaultComponentAnyFlags  +  defaultComponentAnyManufacturer),
   defaultComponentAnyFlagsAnyManufacturerAnySubType =  (defaultComponentAnyFlags + defaultComponentAnyManufacturer +  defaultComponentAnySubType)
};

Constants
defaultComponentIdentical

The Component Manager places the component specified in the call to SetDefaultComponent in front of all other components that have the same component description.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

defaultComponentAnyFlags

The Component Manager ignores the value of the componentFlags field during the reorder operation.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

defaultComponentAnyManufacturer

The Component Manager ignores the value of the componentManufacturer field during the reorder operation.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

defaultComponentAnySubType

The Component Manager ignores the value of the componentSubType field during the reorder operation.

Available in Mac OS X v10.0 and later.

Declared in Components.h.

defaultComponentAnyFlagsAnyManufacturer

Available in Mac OS X v10.0 and later.

Declared in Components.h.

defaultComponentAnyFlagsAnyManufacturerAnySubType

Available in Mac OS X v10.0 and later.

Declared in Components.h.

Discussion

The SetDefaultComponent function uses these values in the flags parameter to control which component description fields the Component Manager examines during the reorder operation.

Result Codes

The result codes defined by the Component Manager are listed below.

Result CodeValueDescription
invalidComponentID -3000

Invalid component ID.

Available in Mac OS X v10.0 and later.

validInstancesExist -3001

This component has open connections.

Available in Mac OS X v10.0 and later.

componentNotCaptured -3002

This component has not been captured.

Available in Mac OS X v10.0 and later.

componentDontRegister -3003

Available in Mac OS X v10.0 and later.
unresolvedComponentDLLErr -3004

Available in Mac OS X v10.0 and later.
retryComponentRegistrationErr -3005

Available in Mac OS X v10.0 and later.
badComponentSelector 0x80008002

Component does not support the specified request code.

Available in Mac OS X v10.0 and later.

badComponentInstance 0x80008001

Invalid component passed to Component Manager.

Available in Mac OS X v10.0 and later.

Gestalt Constants

You can check for version and feature availability information by using the Component Manager selectors defined in the Gestalt Manager. For more information, see Gestalt Manager Reference.



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© 2001, 2006 Apple Computer, Inc. All Rights Reserved. (Last updated: 2006-07-17)

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