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Re: Calling a Cocoa library from C
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Re: Calling a Cocoa library from C


  • Subject: Re: Calling a Cocoa library from C
  • From: Greg Guerin <email@hidden>
  • Date: Sat, 12 Nov 2011 15:48:00 -0700

Nathan Sims wrote:

Hmm, if not a global, where would the declaration go? The C function certainly shouldn't return it, so if it is to remain persistent across calls, wouldn't the logical (the only?) place for it be as a global in the library's .m file?


Why shouldn't the C function return it? As far as C is concerned, an object pointer is just an opaque pointer. Handle it like any other opaque pointer.

Example:

void * setup_data()
{
return (void *) [[ObjcCode alloc]init];
}
int get_float_data( void * ptrFrom_setup_data, float *result1, float *result2)
{
ObjcCode *obj = (ObjcCode *) ptrFrom_setup_data;


	NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

	[obj call];
	*result1 = [more stuff];
	etc.;

	[pool drain];
	return 0;
}
void quit_data( void * ptrFrom_setup_data )
{
	[(ObjcCode *)ptrFrom_setup_data release];
}

  -- GG


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