ADC Home > Reference Library > Reference > Carbon > File Management > Alias Manager Reference >

Next Page > Hide TOC

Alias Manager Reference

Framework
CoreServices/CoreServices.h
Declared in
Aliases.h

Overview

The Alias Manager creates and resolves alias records, which are data structures that describe file system objects (files, directories, and volumes.) An alias record contains a "fingerprint" of a file system object. You can store the alias record instead of a file system reference, and use the Alias Manager to find the object again when it's needed. The Alias Manager contains algorithms for locating objects that have been moved, renamed, copied, or restored from backup.

The exact makeup of an alias record depends on the file system in which the object resides. The Alias Manager takes advantage of persistent object ids, creation dates, file types, creator codes and the like if they are available. By default, an object at the location stored in the alias record will be considered a stronger match than an object with the same file id in a different location. (You can alter this behavior by passing flags to the functions that resolve the alias.)

The Alias Manager supports two types of alias records. The standard alias contains as much information as the Alias Manager can gather from the underlying file system. The minimal alias only stores a subset of the information in a standard alias record. A minimal alias may be used when the object is unlikely to move, the reference is to be short-lived, or space is a critical issue (the exact space savings depends on the underlying file system format.) The standard alias is the preferred format because it is more robust.

The Finder supports the creation and use of alias files that contain alias records. Currently, Mac OS X does not provide a way for other applications to create these alias files. The Alias Manager can identify and resolve Finder alias files, but it cannot create them.

Functions by Task

Creating and Updating Alias Records

Getting Alias Size

Getting and Setting Alias User Types

Resolving and Reading Alias Records

Working With Finder Alias Files

Working With Universal Procedure Pointers to Alias Manager Callbacks

Deprecated Functions

Alias Manager functions that use the FSSpec data type have been deprecated. Instead, you should use the equivalent FSRef–based functions, which include support for features such as unicode and long filenames. For more information on FSSpec and FSRef types, see File Manager Reference.

Functions

DisposeAliasFilterUPP

Disposes of a universal procedure pointer (UPP) to an alias filtering callback function.

void DisposeAliasFilterUPP (
   AliasFilterUPP userUPP
);

Parameters
userUPP

The UPP to dispose of.

Discussion

See AliasFilterProcPtr for more information on alias filtering callback functions.

Availability
Declared In
Aliases.h

FSCopyAliasInfo

Returns information from an alias handle.

OSStatus FSCopyAliasInfo (
   AliasHandle inAlias,
   HFSUniStr255 *targetName,
   HFSUniStr255 *volumeName,
   CFStringRef *pathString,
   FSAliasInfoBitmap *whichInfo,
   FSAliasInfo *info
);

Parameters
inAlias

A handle to the alias record from which to get information.

targetName

A pointer to a string that, on return, contains the name of the target item. Pass NULL if you do not want this information returned.

volumeName

A pointer to a string that, on return, contains the name of the volume the target resides on. Pass NULL if you do not want this information returned.

pathString

A pointer a CFString that, on return, contains the POSIX path to the target. Pass NULL if you do not want this information returned.

whichInfo

A pointer to a variable of type FSAliasInfoBitmap. On return, this field indicates which fields in the alias information block, specified in the info parameter, contain valid data. See “Alias Information Masks” for a description of the values that may be returned here. This parameter may be NULL.

info

A pointer to a structure of type FSAliasInfo. On return, this structure contains information about the alias. Pass NULL if you do not want this information returned.

Return Value

A result code.

Discussion

This function returns the requested information from the alias handle passed in the inAlias parameter. The information is gathered only from the alias record, so it may not match what is on disk. No disk input/output is performed.

The FSCopyAliasInfo function adds support for unicode filenames and filenames longer than 32 bytes. It replaces the GetAliasInfo function.

Availability
Declared In
Aliases.h

FSFollowFinderAlias

Resolves an alias record obtained from a Finder alias file.

OSErr FSFollowFinderAlias (
   FSRef *fromFile,
   AliasHandle alias,
   Boolean logon,
   FSRef *target,
   Boolean *wasChanged
);

Parameters
fromFile

A pointer to the file to use for a first attempt at a relative resolution; pass a pointer to the alias file's FSRef for this parameter.

alias

A handle to the alias record taken from the alias file's resources.

logon

If true, the Alias Manager attempts to mount a volume if necessary to complete the resolution of the alias.

target

A pointer to an FSRef structure. On return, this FSRef refers to the target found by the resolution.

wasChanged

A pointer to a Boolean value. FSFollowFinderAlias sets this value to true if it has updated the alias record.

Return Value

A result code.

Availability
Declared In
Aliases.h

FSIsAliasFile

Determines whether a file system object is an alias file, a data file, or a folder.

OSErr FSIsAliasFile (
   const FSRef *fileRef,
   Boolean *aliasFileFlag,
   Boolean *folderFlag
);

Parameters
fileRef

A pointer to the file system object to test.

aliasFileFlag

A pointer to a Boolean variable. On return, a value of TRUE indicates that the object specified in the fileRef parameter is an alias file. A value of FALSE indicates that the object is not an alias file.

folderFlag

A pointer to a Boolean variable. On return, a value of TRUE indicates that the object specified in the fileRef parameter is a folder. A value of FALSE indicates that the object is a file.

Return Value

A result code.

Discussion

Table 1 summarizes the information that this function provides about the object specified in the fileRef parameter:

Table 1  Information about a file system object

Alias flag

Folder flag

Object kind

T

F

Alias file

F

F

Data file

F

T

Folder

Note that if fileRef is an alias file, this function does not provide any information about the object to which the alias refers. To find out whether this object is a file or a folder, you can use FSResolveAliasFile.

Availability
Related Sample Code
Declared In
Aliases.h

FSMatchAliasBulk

Identifies a list of possible matches for an alias.

OSStatus FSMatchAliasBulk (
   const FSRef *fromFile,
   unsigned long rulesMask,
   AliasHandle inAlias,
   short *aliasCount,
   FSRef *aliasList,
   Boolean *needsUpdate,
   FSAliasFilterProcPtr aliasFilter,
   void *yourDataPtr
);

Parameters
fromFile

A pointer to the starting point for a relative search. You may pass NULL if you do not want this function to perform a relative search. By default, this function performs a relative search only if the absolute search does not find a match. If you want to perform the relative search first, you should pass kARMSearchRelFirst in the rulesMask parameter.

rulesMask

A set of rules to guide the resolution. Pass the sum of all of the rules you want to invoke. For a description of the values you can use in this parameter, see “Matching Constants.”

inAlias

A handle to the alias record to be resolved.

aliasCount

On input, a pointer to the maximum number of possible matches to return. On output, the actual number of matches returned.

aliasList

A pointer to an array of FSRef structures. On output, this array holds the results of the search, a list of possible candidates.

needsUpdate

A pointer to a Boolean flag that, on output, indicates whether the alias record needs to be updated. For more information about this parameter, see the Discussion.

aliasFilter

An optional application-defined filter function. The Alias Manager calls your filter function each time it identifies a possible match or after the search has continued for three seconds without a match. Your filter function returns a Boolean value that determines whether the possible match is discarded (true) or added to the list of possible targets (false). It can also terminate the search by setting the variable parameter quitFlag. See FSAliasFilterProcPtr for a description of the filter function.

yourDataPtr

A pointer to data to be passed to the filter function, or NULL. The yourDataPtr parameter can point to any data your application might need in the filter function.

Return Value

A result code. If the Alias Manager finds the specified volume and parent directory but fails to find the target file or directory in that location, the return value is fnfErr and the elements in the aliasList parameter are not valid.

Discussion

After it identifies a target, this function compares some key information about the target with the same information in the record. If the information does not match, this function sets the needsUpdate flag to true. This function also sets the needsUpdate flag to true if it identifies a list of possible matches rather than a single match or if kARMsearchRelFirst is set in the rulesMask parameter but the target is identified through either an absolute search or an exhaustive search. Otherwise, this function sets the needsUpdate flag to false. This function always sets the needsUpdate flag to false when resolving an alias created by FSNewAliasMinimal. To update the alias record to reflect the final results of the resolution, use the function FSUpdateAlias.

Availability
Declared In
Aliases.h

FSNewAlias

Creates a new alias record, given a target file or directory.

OSErr FSNewAlias (
   const FSRef *fromFile,
   const FSRef *target,
   AliasHandle *inAlias
);

Parameters
fromFile

A pointer to the starting point for a relative search. You may pass NULL if you do not need relative search information in the alias record. The files or directories specified in the fromFile and target parameters must reside on the same volume.

target

A pointer to the target file or directory of the alias.

inAlias

A pointer to an alias handle. On return, this handle refers to the newly created alias record. If the function fails to create an alias record, it sets inAlias to NULL.

Return Value

A result code. If the specified target is valid, this function creates an alias record for the target and returns noErr. Any other return value indicates that this function did not create an alias record.

Discussion

The FSNewAlias function creates an alias record that describes the specified target. It allocates the storage, fills in the record, and puts a record handle to that storage in the inAlias parameter. FSNewAlias records the full pathname of the target and a collection of other information relevant to locating the target, verifying the target, and mounting the target’s volume, if necessary. You can have FSNewAlias store relative search information as well by supplying a starting point for a relative search.

Availability
Related Sample Code
Declared In
Aliases.h

FSNewAliasFromPath

Creates a new alias record, given the pathname of the target file or directory.

OSErr FSNewAliasFromPath (
   const char *fromFilePath,
   const char *targetPath,
   OptionBits flags,
   AliasHandle *inAlias,
   Boolean *isDirectory
);

Parameters
fromFilePath

A C string that specifies the starting point for a relative search. The string should contain a UTF-8 pathname. You may pass NULL if you do not need relative search information in the alias record.

targetPath

A C string that contains the full UTF-8 pathname of the target object.

flags

Reserved for future use. Currently, you should pass 0.

inAlias

A pointer to an alias handle. On output, this handle refers to the newly created alias record.

isDirectory

A pointer to a Boolean value. On input, if the target does not exist, set the value to true if the target is a directory or false if it is not. (Pass NULL if you are not sure whether the target is a directory.) On output, if the target exists, the value is true if the target is a directory, false if it is not.

Return Value

A result code. For more information, see the Discussion.

Discussion

If the specified target exists, this function creates an alias record for the target and returns noErr. If the parent directory specified in the target pathname exists but the target itself does not exist, this function creates an alias record for the target and returns fnfErr. Any other return value indicates that this function did not create an alias record.

Availability
Declared In
Aliases.h

FSNewAliasMinimal

Creates a new minimal alias record, given a target file or directory.

OSErr FSNewAliasMinimal (
   const FSRef *target,
   AliasHandle *inAlias
);

Parameters
target

A pointer to the target of the alias record.

inAlias

A pointer to an alias handle. On return, this handle refers to the newly created alias record. If the function fails to create an alias record, it sets inAlias to NULL.

Return Value

A result code. If the specified target is valid, this function creates an alias record for the target and returns noErr. Any other return value indicates that this function did not create an alias record.

Discussion

The FSNewAliasMinimal function creates an alias record that contains only the minimum information necessary to describe the target. The FSNewAliasMinimal function uses the standard alias record data structure, but it fills in only parts of the record.

The FSResolveAlias function never updates a minimal alias record.

Availability
Declared In
Aliases.h

FSNewAliasMinimalUnicode

Creates a minimal alias, given the Unicode name and parent directory of the target.

OSErr FSNewAliasMinimalUnicode (
   const FSRef *targetParentRef,
   UniCharCount targetNameLength,
   const UniChar *targetName,
   AliasHandle *inAlias,
   Boolean *isDirectory
);

Parameters
targetParentRef

A pointer to the parent directory of the target.

targetNameLength

The number of Unicode characters in the target's name.

targetName

A pointer to the Unicode name of the target.

inAlias

A pointer to an alias handle. On return, this handle refers to the newly created alias record.

isDirectory

A pointer to a Boolean value. On input, if the target does not exist, set the value to true if the target is a directory or false if it is not. (Pass NULL if you are not sure whether the target is a directory.) On output, if the target exists, the value is true if the target is a directory, false if it is not.

Return Value

A result code. For more information, see the Discussion.

Discussion

If the specified target exists, this function creates an alias record for the target and returns noErr. If the parent directory exists but the target itself does not exist, this function creates an alias record for the target and returns fnfErr. Any other return value indicates that this function did not create an alias record.

Availability
Declared In
Aliases.h

FSNewAliasUnicode

Creates a new alias record, given the Unicode name and parent directory of the target.

OSErr FSNewAliasUnicode (
   const FSRef *fromFile,
   const FSRef *targetParentRef,
   UniCharCount targetNameLength,
   const UniChar *targetName,
   AliasHandle *inAlias,
   Boolean *isDirectory
);

Parameters
fromFile

A pointer to the starting point for a relative search. You may pass NULL if you do not need relative search information in the alias record.

targetParentRef

A pointer to the parent directory of the target.

targetNameLength

The number of Unicode characters in the target's name.

targetName

A pointer to the Unicode name of the target.

inAlias

A pointer to an alias handle. On return, this handler refers to the newly created alias record.

isDirectory

A pointer to a Boolean value. On input, if the target does not exist, set the value to true if the target is a directory or false if it is not. (Pass NULL if you are not sure whether the target is a directory.) On output, if the target exists, the value is true if the target is a directory, false if it is not.

Return Value

A result code. For more information, see the Discussion.

Discussion

If the specified target exists, this function creates an alias record for the target and returns noErr. If the parent directory exists but the target itself does not exist, this function creates an alias record for the target and returns fnfErr. Any other return value indicates that this function did not create an alias record.

Availability
Declared In
Aliases.h

FSResolveAlias

Returns an FSRef to the single most likely target of an alias record.

OSErr FSResolveAlias (
   const FSRef *fromFile,
   AliasHandle alias,
   FSRef *target,
   Boolean *wasChanged
);

Parameters
fromFile

A pointer to the starting point for a relative search. If you pass NULL in this parameter, FSResolveAlias performs only an absolute search. If you pass a pointer to a valid FSRef in the fromFile parameter, FSResolveAlias performs a relative search for the target, followed by an absolute search only if the relative search fails. If you want to perform an absolute search followed by a relative search, you should use the function FSMatchAliasBulk.

alias

A handle to the alias record to be resolved and, if necessary, updated.

target

A pointer to an FSRef. On successful return, this FSRef describes the target of the alias record. This parameter must point to a valid FSRef structure.

wasChanged

A pointer to a Boolean value indicating, on return, whether the alias record in the alias parameter was updated because it contained some outdated information about the target. If it updates the alias record, FSResolveAlias sets the wasChanged parameter to true. Otherwise, it sets it to false. (FSResolveAlias never updates a minimal alias, so it never sets wasChanged to true when resolving a minimal alias.

Return Value

A result code. When it finds the specified volume and parent directory but fails to find the target file or directory in that location, FSResolveAlias returns fnfErr. Note that the FSRef in the alias parameter is not valid in this case.

Discussion

The FSResolveAlias function performs a fast search for the target of the alias. If the resolution is successful, FSResolveAlias returns (in the target parameter) the FSRef for the target file system object, updates the alias record if necessary, and reports (through the wasChanged parameter) whether the record was updated. If the target is on an unmounted AppleShare volume, FSResolveAlias automatically mounts the volume. If the target is on an unmounted ejectable volume, FSResolveAlias asks the user to insert the volume. The FSResolveAlias function exits after it finds one acceptable target.

After it identifies a target, FSResolveAlias compares some key information about the target with the information in the alias record. If the information differs, FSResolveAlias updates the record to match the target.

The FSResolveAlias function displays the standard dialogs when it needs input from the user, such as a name and password for mounting a remote volume. The user can cancel the resolution through these dialogs.

Availability
Related Sample Code
Declared In
Aliases.h

FSResolveAliasFile

Resolves an alias contained in an alias file.

OSErr FSResolveAliasFile (
   FSRef *theRef,
   Boolean resolveAliasChains,
   Boolean *targetIsFolder,
   Boolean *wasAliased
);

Parameters
theRef

A pointer to the alias file you plan to open. If the function completes successfully, this FSRef describes to the file or the directory referred to by the alias file.

resolveAliasChains

A Boolean value. Set this parameter to TRUE if you want FSResolveAliasFile to resolve all aliases in a chain (for example, an alias file that refers to an alias file and so on), stopping only when it reaches the target file. Set this parameter to FALSE if you want to resolve only one alias file, even if the target is another alias file.

targetIsFolder

A pointer to a Boolean value. The FSResolveAliasFile function returns TRUE in this parameter if the FSRef in the parameter theRef points to a directory or a volume; otherwise, FSResolveAliasFile returns FALSE in this parameter.

wasAliased

A pointer to a Boolean value. The FSResolveAliasFile function returns TRUE in this parameter if the FSRef in the parameter theRef points to an alias; otherwise, FSResolveAliasFile returns FALSE in this parameter.

Return Value

A result code. When it finds the specified volume and parent directory but fails to find the target file or directory in that location, FSResolveAliasFile returns fnfErr.

Discussion

If your application bypasses the Finder when manipulating documents, it should check for and resolve aliases itself by using the FSResolveAliasFile function.

The FSResolveAliasFile function first checks the catalog file for the file or directory specified in the parameter theRef to determine whether it is an alias and whether it is a file or a directory. If the object is not an alias, FSResolveAliasFile leaves theRef unchanged, sets the targetIsFolder parameter to TRUE for a directory or volume and FALSE for a file, sets wasAliased to FALSE, and returns noErr. If the object is an alias, FSResolveAliasFile resolves it, places the target in the parameter theRef, and sets the wasAliased flag to TRUE.

If FSResolveAliasFile receives an error code while resolving an alias, it leaves the input parameters as they are and exits, returning an error code. FSResolveAliasFile can return any Resource Manager or File Manager errors.

Availability
Declared In
Aliases.h

FSResolveAliasFileWithMountFlags

Resolves an alias contained in an alias file.

OSErr FSResolveAliasFileWithMountFlags (
   FSRef *theRef,
   Boolean resolveAliasChains,
   Boolean *targetIsFolder,
   Boolean *wasAliased,
   unsigned long mountFlags
);

Parameters
theRef

A pointer to the alias file you plan to open. If the function completes successfully, this FSRef describes the file or the directory referred to by the alias file.

resolveAliasChains

A Boolean value. Set this parameter to TRUE if you want FSResolveAliasFileWithMountFlags to resolve all aliases in a chain (for example, an alias file that refers to an alias file and so on), stopping only when it reaches the target file. Set this parameter to FALSE if you want to resolve only one alias file, even if the target is another alias file.

targetIsFolder

A pointer to a Boolean value. The FSResolveAliasFileWithMountFlags function returns TRUE in this parameter if the FSRef in the parameter theRef points to a directory or a volume; otherwise, FSResolveAliasFileWithMountFlags returns FALSE in this parameter.

wasAliased

A pointer to a Boolean value. The FSResolveAliasFileWithMountFlags function returns TRUE in this parameter if the FSRef in the parameter theRef points to an alias; otherwise, FSResolveAliasFileWithMountFlags returns FALSE in this parameter.

mountFlags

Options controlling how the alias file is resolved. See “Volume Mount Options” for a description of the values you can use here. Set this parameter to kResolveAliasFileNoUI to prevent any user interaction, including disk switch alerts, while the alias is being resolved.

Return Value

A result code.

Discussion

The function FSResolveAliasFileWithMountFlags is identical to FSResolveAliasFile with the exception that it provides the mountFlags parameter, allowing callers additional control over how the alias file is resolved.

Availability
Declared In
Aliases.h

FSResolveAliasWithMountFlags

Returns an FSRef to the target of an alias.

OSErr FSResolveAliasWithMountFlags (
   const FSRef *fromFile,
   AliasHandle inAlias,
   FSRef *target,
   Boolean *wasChanged,
   unsigned long mountFlags
);

Parameters
fromFile

A pointer to the starting point for a relative search. If you pass NULL in this parameter, FSResolveAliasWithMountFlags performs an absolute search. If you pass a pointer to a valid FSRef in the fromFile parameter, FSResolveAliasWithMountFlags performs a relative search for the target, followed by an absolute search only if the relative search fails. If you want to perform an absolute search followed by a relative search, you should use the function FSMatchAliasBulk.

inAlias

A handle to the alias record to be resolved and, if necessary, updated.

target

A pointer to an FSRef structure. On successful return, this FSRef refers to the target of the alias record. This parameter must point to a valid FSRef structure.

wasChanged

A pointer to a Boolean value indicating, on return, whether the alias record to be resolved was updated because it contained some outdated information about the target. If it updates the alias record, FSResolveAliasWithMountFlags sets the wasChanged parameter to true. Otherwise, it sets it to false. (FSResolveAliasWithMountFlags never updates a minimal alias, so it never sets wasChanged to true when resolving a minimal alias.

mountFlags

Options controlling how the alias is resolved. See “Volume Mount Options” for a description of the values you can use here. Set this parameter to kResolveAliasFileNoUI to prevent any user interaction while the alias is being resolved.

Return Value

A result code.

Discussion

The function FSResolveAliasWithMountFlags is identical to FSResolveAlias with the exception that it provides the mountFlags parameter, allowing callers additional control over how the alias is resolved.

Availability
Declared In
Aliases.h

FSUpdateAlias

Updates an alias record for a specified target.

OSErr FSUpdateAlias (
   const FSRef *fromFile,
   const FSRef *target,
   AliasHandle alias,
   Boolean *wasChanged
);

Parameters
fromFile

A pointer to the starting point for a relative search. You may pass NULL if you do not need relative search information in the alias record. The two files or directories specified in the fromFile and target parameters must reside on the same volume.

target

A pointer to the target of the alias record.

alias

A handle to the alias record to be updated.

wasChanged

A pointer to a Boolean value that, on output, indicates whether the newly constructed alias record is different from the old one. If the new record is exactly the same as the old one, the value is false. Otherwise, the value is true. Check this parameter to determine whether you need to save an updated record.

Return Value

A result code.

Discussion

This function rebuilds the entire alias record and fills it in as the FSNewAlias function would. The FSUpdateAlias function always creates a complete alias record. When you use FSUpdateAlias to update a minimal alias record, you convert the minimal record to a complete record.

Availability
Declared In
Aliases.h

GetAliasSize

Gets the size of an alias record referenced by a handle.

Size GetAliasSize (
   AliasHandle alias
);

Parameters
alias

A handle to the alias record from which to get the information.

Return Value

The size of the alias record.

Discussion

The returned size is smaller than the size returned by the function GetHandleSize if any custom data is added. This routine is thread safe.

Availability
Declared In
Aliases.h

GetAliasSizeFromPtr

Gets the size of an alias record referenced by a pointer.

Size GetAliasSizeFromPtr (
   const AliasRecord *alias
);

Parameters
alias

A pointer to the alias record from which to get the information.

Return Value

The size of the alias record.

Discussion

This routine is thread safe.

Availability
Declared In
Aliases.h

GetAliasUserType

Gets the user type for an alias record referenced by a handle.

OSType GetAliasUserType (
   AliasHandle alias
);

Parameters
alias

A handle to the alias record from which to get the user type.

Return Value

The user type associated with the alias.

Discussion

This routine is thread safe.

Availability
Declared In
Aliases.h

GetAliasUserTypeFromPtr

Gets the user type for the alias record referenced by a pointer.

OSType GetAliasUserTypeFromPtr (
   const AliasRecord *alias
);

Parameters
alias

A pointer to the alias record from which to get the user type.

Return Value

The user type associated with the alias.

Discussion

This routine is thread safe.

Availability
Declared In
Aliases.h

InvokeAliasFilterUPP

Calls your alias filtering callback function.

Boolean InvokeAliasFilterUPP (
   CInfoPBPtr cpbPtr,
   Boolean *quitFlag,
   Ptr myDataPtr,
   AliasFilterUPP userUPP
);

Discussion

You should not need to use the function InvokeAliasFilterUPP, as the system calls your alias filtering callback for you.

Availability
Declared In
Aliases.h

NewAliasFilterUPP

Creates a new universal procedure pointer (UPP) to an alias filtering callback function.

AliasFilterUPP NewAliasFilterUPP (
   AliasFilterProcPtr userRoutine
);

Parameters
userRoutine

A pointer to your alias filtering callback function. For more information, see AliasFilterProcPtr.

Return Value

On return, a UPP to the alias filtering callback function.

Availability
Declared In
Aliases.h

SetAliasUserType

Sets the user type for an alias record referenced by a handle.

void SetAliasUserType (
   AliasHandle alias,
   OSType userType
);

Parameters
alias

A handle to the alias record for which to set the user type.

userType

The user type associated with the alias.

Discussion

This routine is thread safe.

Availability
Declared In
Aliases.h

SetAliasUserTypeWithPtr

Sets the user type for the alias record referenced by a pointer.

void SetAliasUserTypeWithPtr (
   AliasPtr alias,
   OSType userType
);

Parameters
alias

A pointer to the alias record for which to set the user type.

userType

The user type associated with the alias.

Discussion

This routine is thread safe.

Availability
Declared In
Aliases.h

Callbacks

AliasFilterProcPtr

Defines a pointer to an alias filtering callback function that filters out possible targets identified by the FSMatchAlias function.

typedef Boolean (*AliasFilterProcPtr) (
   CInfoPBPtr cpbPtr,
   Boolean * quitFlag,
   Ptr myDataPtr
);

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

Boolean MyAliasFilterCallback (
   CInfoPBPtr cpbPtr,
   Boolean * quitFlag,
   Ptr myDataPtr
);

Parameters
cpbPtr

A pointer to a catalog information parameter block. When your function is called, the cpbPtr parameter points to the catalog information parameter block of the possible match (returned by the File Manager function PBGetCatInfo).

quitFlag

On exit, set this to true if you want to terminate the search.

myDataPtr

A pointer to any customized data that your application passed when it called FSMatchAlias. This parameter allows your filter function to access any data that your application has set up on its own.

Return Value

Your function should return true to indicate that the possible match is to be discarded, or false to indicate that the possible match is to be added to the list of possible targets.

Discussion

You can write your own filter function to examine possible targets identified by the FSMatchAlias function. The FSMatchAlias function calls your filter function each time it identifies a possible match.

Availability
Declared In
Aliases.h

FSAliasFilterProcPtr

Defines a pointer to an alias filtering callback function that filters out possible targets identified by the FSMatchAliasBulk function.

typedef Boolean (*FSAliasFilterProcPtr) (
   FSRef *ref,
   Boolean *quitFlag,
   Ptr myDataPtr
);

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

Boolean MyAliasFilterCallback (
   FSRef *ref,
   Boolean *quitFlag,
   Ptr myDataPtr
);

Parameters
ref

A pointer to a file system object. When your function is called, the ref parameter points to the possible match.

quitFlag

On output, set this Boolean flag to true if you want to terminate the search.

myDataPtr

A pointer to any customized data that your application passed when it called FSMatchAliasBulk. This parameter allows your filter function to access any data that your application has set up on its own.

Return Value

Your function should return true to indicate that the possible match is to be discarded, or false to indicate that the possible match is to be added to the list of possible targets.

Discussion

You can write your own filter function to examine possible targets identified by the FSMatchAliasBulk function. The FSMatchAliasBulk function calls your filter function each time it identifies a possible match.

Availability
Declared In
Aliases.h

Data Types

AliasInfoType

Defines the alias record information type used in the index parameter of GetAliasInfo.

typedef short AliasInfoType;

Availability
Declared In
Aliases.h

AliasFilterUPP

Defines a universal procedure pointer (UPP) to an alias filtering function.

typedef AliasFilterProcPtr AliasFilterUPP;

Discussion

See AliasFilterProcPtr for more information on alias filtering functions.

Availability
Declared In
Aliases.h

AliasRecord

Defines an alias record.

struct AliasRecord {
   OSType userType;
   unsigned short aliasSize;
};
typedef struct AliasRecord              AliasRecord;
typedef AliasRecord *                   AliasPtr;
typedef AliasPtr *                      AliasHandle;

Fields
userType

A 4-byte field that can contain application-specific data. When an alias record is created, this field contains 0. Your application can use this field for its own purposes.

aliasSize

The size, in bytes, assigned to the alias record at the time of its creation or updating. This is the total size of the record, including the userType and aliasSize fields, as well as the variable-length data that is private to the Alias Manager.

Discussion

The Alias Manager uses alias records to store information that allows it to locate an object in the file system.

Availability
Declared In
Aliases.h

FSAliasInfo

Defines an information block passed to the FSCopyAliasInfo function.

struct FSAliasInfo {
   UTCDateTime volumeCreateDate;
   UTCDateTime targetCreateDate;
   OSType fileType;
   OSType fileCreator;
   UInt32 parentDirID;
   UInt32 nodeID;
   UInt16 filesystemID;
   UInt16 signature;
   Boolean volumeIsBootVolume;
   Boolean volumeIsAutomounted;
   Boolean volumeIsEjectable;
   Boolean volumeHasPersistentFileIDs;
   Boolean isDirectory;
};
typedef struct FSAliasInfo FSAliasInfo;
typedef FSAliasInfo * FSAliasInfoPtr;

Fields
volumeCreateDate

The creation date of the volume on which the alias target resides.

targetCreateDate

The creation date of the alias target.

fileType

The file type of the target.

fileCreator

The creator code of the target.

parentDirID

The directory ID of the target’s parent directory.

nodeID

The ID of the file or directory that is the alias target.

filesystemID

The filesystem ID.

signature

The volume signature of the volume on which the target resides.

volumeIsBootVolume

A Boolean value indicating whether the volume is the boot volume.

volumeIsAutomounted

A Boolean value indicating whether the volume is automounted.

volumeIsEjectable

A Boolean value indicating whether the volume is ejectable.

volumeHasPersistentFileIDs

A Boolean value indicating whether the volume has persistent file ID’s.

isDirectory

A Boolean value indicating whether the alias target is a directory.

Availability
Declared In
Aliases.h

Constants

Alias Information Masks

Returned by the FSCopyAliasInfo function to indicate which fields of the alias information structure contain valid data.

typedef UInt32 FSAliasInfoBitmap;
enum {
   kFSAliasInfoNone = 0x00000000,
   kFSAliasInfoVolumeCreateDate = 0x00000001,
   kFSAliasInfoTargetCreateDate = 0x00000002,
   kFSAliasInfoFinderInfo = 0x00000004,
   kFSAliasInfoIsDirectory = 0x00000008,
   kFSAliasInfoIDs = 0x00000010,
   kFSAliasInfoFSInfo = 0x00000020,
   kFSAliasInfoVolumeFlags = 0x00000040
};

Constants
kFSAliasInfoNone

None of the alias information is valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoVolumeCreateDate

The volume creation date in the volumeCreateDate field is valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoTargetCreateDate

The creation date of the alias target, in the targetCreateDate field, is valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoFinderInfo

The file type and creator information, in the fileType and fileCreator fields, is valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoIsDirectory

The information in the isDirectory field is valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoIDs

The parent directory ID and alias target ID, in the parentDirID and nodeID fields, are valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoFSInfo

The filesystem ID and signature, in the filesystemID and signature fields, are valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

kFSAliasInfoVolumeFlags

The volume information, in the volumeIsBootVolume, volumeIsAutomounted, volumeIsEjectable, and volumeHasPersistentFileIDs fields, is valid.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

Volume Mount Options

Specify how an alias should be resolved.

enum {
   kResolveAliasFileNoUI = 0x00000001,
   kResolveAliasTryFileIDFirst = 0x00000002
};

Constants
kResolveAliasFileNoUI

The Alias Manager should resolve the alias without presenting a user interface.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kResolveAliasTryFileIDFirst

The Alias Manager should search for the alias target using file IDs before searching using the path.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

Discussion

The FSResolveAliasWithMountFlags, FSResolveAliasFileWithMountFlags, ResolveAliasWithMountFlags, ResolveAliasFileWithMountFlags, and ResolveAliasFileWithMountFlagsNoUI functions take these constants in the mountFlags parameter, allowing you to specify how the alias should be resolved.

Matching Constants

Specify the matching criteria for the alias matching functions.

enum {
   kARMMountVol = 0x00000001,
   kARMNoUI = 0x00000002,
   kARMMultVols = 0x00000008,
   kARMSearch = 0x00000100,
   kARMSearchMore = 0x00000200,
   kARMSearchRelFirst = 0x00000400,
   kARMTryFileIDFirst = 0x00000800
};

Constants
kARMMountVol

Automatically try to mount the target’s volume if it is not mounted.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kARMNoUI

Stop if a search requires user interaction, such as a password dialog box when mounting a remote volume. If user interaction is needed and kARMNoUI is in effect, the search fails.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kARMMultVols

Search all mounted volumes. The search begins with the volume on which the target resided when the record was created. When you specify a fast search of all mounted volumes, MatchAlias performs a formal fast search only on the volume described in the alias record. On all other volumes it looks for the target by ID or by name in the directory with the specified parent directory ID. When you specify an exhaustive search of multiple volumes, MatchAlias performs the same search on all volumes. When resolving an alias record created by NewAliasMinimalFromFullPath, MatchAlias ignores this flag.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kARMSearch

Perform a fast search for the alias target. If kARMSearchRelFirst is not set, perform an absolute search first, followed by a relative search only if the value of the fromFile parameter is not NULL and the list of matches is not full.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kARMSearchMore

Perform an exhaustive search for the alias target. On HFS volumes, the exhaustive search uses the File Manager function PBCatSearch to identify candidates with matching creation date, type, and creator. The PBCatSearch function is available only on HFS volumes and only on systems running version 7.0 or later. On MFS volumes or HFS volumes that do not support PBCatSearch, the exhaustive search makes a series of indexed calls to File Manager functions, using the same search criteria. If you set kARMSearchMore and either or both of kARMSearch and kARMSearchRelFirst, MatchAlias performs the fast search first.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kARMSearchRelFirst

If kARMSearch is also set, perform a relative search before the absolute search. (If kARMSearch is also set and the target is found through the absolute search, MatchAlias sets the needsUpdate flag to true.) If neither kARMSearch nor kARMSearchMore is set, perform only a relative search. If kARMSearch is not set but kARMSearchMore is set, perform a relative search followed by an exhaustive search.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

kARMTryFileIDFirst

Perform a search using the file ID of the target before searching using the path.

Available in Mac OS X v10.2 and later.

Declared in Aliases.h.

Discussion

The FSMatchAlias, FSMatchAliasNoUI, MatchAliasNoUI and MatchAlias functions use these constants to specify the matching criteria by passing a sum of these constants in the rulesMask parameter. You must specify at least one of the last three parameters: kARMSearch, kARMSearchMore, and kARMSearchRelFirst.

Alias Resource Type

Specifies the file type of an alias resource file.

enum {
   rAliasType = 'alis'
};

Information Type Constants

The GetAliasInfo function uses these constants in the index parameter.

enum {
   asiZoneName = -3,
   asiServerName = -2,
   asiVolumeName = -1,
   asiAliasName = 0,
   asiParentName = 1
};

Constants
asiZoneName

If the record represents a target on an AppleShare volume, retrieve the server’s zone name. Otherwise, return an empty string.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

asiServerName

If the record represents a target on an AppleShare volume, retrieve the server name. Otherwise, return an empty string.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

asiVolumeName

Return the name of the volume on which the target resides.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

asiAliasName

Return the name of the target.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

asiParentName

Return the name of the parent directory of the target of the record. If the target is a volume, return the volume name.

Available in Mac OS X v10.0 and later.

Declared in Aliases.h.

Gestalt Constants

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



Next Page > Hide TOC

© 2003, 2006 Apple Computer, Inc. All Rights Reserved. (Last updated: 2006-12-05)

Did this document help you?
Yes: Tell us what works for you.
It’s good, but: Report typos, inaccuracies, and so forth.
It wasn’t helpful: Tell us what would have helped.