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Gestalt

Gestalt Get information about the operating environment

#include <GestaltEqu.h> Gestalt Manager

OSErr Gestalt( selector, response );

OSType selector ; Gestalt selector code

long *response ; 4-byte return result

returns Error Code; 0=no error

Gestalt provides your application with information about specific hardware

and software features.

selector is either a pre defined code or an application- defined code

requesting information on a specific hardware or software feature

(see Using the Gestalt Manager for a list of selector codes).

response is the return value that provides the requested

information. Gestalt must already recognize the selector parameter

in order to return a response.

Returns: an operating system Error Code.

It will be one of:

noErr (0) No error

gestaltUnknown (-5550) Could not obtain the response

gestaltUndefSelectorErr (-5551) Un defined selector

Notes: Gestalt returns the results from all function selectors in a 4-byte long

integer. Where not all 4 bytes are needed, the result is expressed in the

low-order bytes.

Being passed a pre defined selector code doesn't cause Gestalt to move or

purge memory and therefore may be called even at interrupt time.

However, application- defined selector codes may move or purge memory

and applications can alter Gestalt's pre defined selector functions. Given

all of that, you should always assume that Gestalt might always move or

purge memory.

THINK C 5.0 or later, THINK Pascal 4.0 or later and MPW 3.2 or later

contain glue that make it possible to call Gestalt under System versions

which do not support Gestalt (earlier than System 6.0.4). When possible,

the glue will call other traps in order to obtain the information requested.

If the selector is not available, a gestaltUndefSelectorErr will be returned.

Note that if you are programming in assembly language, this glue is not

provided. The following selectors are made available by this glue:

 gestaltVersion
 gestaltMachineType
 gestaltSystemVersion
 gestaltProcessorType
 gestaltFPUType
 gestaltQuickdrawVersion
 gestaltKeyboardType
 gestaltAppleTalkVersion
 gestaltMMUType
 gestaltPhysicalRAMSize
 gestaltLogicalRAMSize

All other selectors will return a gestaltUndefSelectorErr under System

versions which do not support Gestalt..

See Using the Gestalt Manager for additional sample code which

demonstrates the use of Gestalt.

Example

#include 
#include 
static char * processor[] = {
"",
"mc68000",
"mc68010",
"mc68020",
"mc68030",
"mc68040
};
static char *fpu[] = {
"",
"mc68881",
"mc68882",
"mc68040 built-in
};
main ()
{
long  gestaltAnswer;
OSErr  gestaltErr;
/* Determine whether we can use Gestalt or not, and if so, what version */
 gestaltErr = Gestalt ( gestaltVersion, & gestaltAnswer);
if (!  gestaltErr) {
 printf ("Gestalt is  available, version %ld\n",  gestaltAnswer);
 printf ("\n");
/* Determine the processor type */
Gestalt ( gestaltProcessorType, & gestaltAnswer);
if ( gestaltAnswer > 5) /* A constant for a processor we don't */
/* recognize has been returned */
 printf ("Processor type: %s\n",  processor[0]);
else
 printf ("Processor type: %s\n",  processor[ gestaltAnswer]);
/* Determine the coprocessor type */
Gestalt ( gestaltFPUType, & gestaltAnswer);
 printf ("FPU type: %s\n", fpu [ gestaltAnswer]);
} else
 printf ("Gestalt not  available\n");
}

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