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Inside Macintosh: Operating System Utilities /

Chapter 1 - Gestalt Manager / Gestalt Manager Reference

Gestalt Manager Routines / Adding a Selector Code

NewGestalt

You can use the NewGestalt function to add a selector code to those already recognized by Gestalt.

FUNCTION NewGestalt (selector: OSType; 
                     gestaltFunction: SelectorFunctionUUP)
                     : OSErr;

selector

The selector code you're adding, which is a four-character sequence of type OSType.

gestaltFunction

A pointer to the selector function that Gestalt executes when it receives the new selector code.

DESCRIPTION

The NewGestalt function registers a specified selector code with the Gestalt Manager so that when Gestalt is called with that selector code, the specified selector function is executed. The function result of NewGestalt is a result code.

Before calling NewGestalt, you must define a selector function and install it in the system heap. The selector function must conform to the interface defined in "Adding a New Selector Code" beginning on page 1-10.

Registering with the Gestalt Manager is a way for software such as system extensions to make their presence known to potential users of their services.

SPECIAL CONSIDERATIONS

The NewGestalt function might move memory and should not be called at interrupt time.

ASSEMBLY-LANGUAGE INFORMATION

The registers on entry and exit for the NewGestalt function are

Registers on entry
A0	Address of new selector function
D0	Selector code

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
memFullErr	-108	Ran out of memory
gestaltDupSelectorErr	-5552	Selector already exists
gestaltLocationErr	-5553	Function not in system heap

SEE ALSO

See "Adding a New Selector Code" beginning on page 1-10 for a sample selector function and a sample procedure that installs it. For information about the Gestalt function, see page 1-31.