//gcc -o libmylib.so -shared -fpic mylib.c -lpthread
#include "mylib.h"
#include <pthread.h>

static lib_work_done_callback_t GCB;
static void *GData;

static void *run( void *Arg )
{
	sleep( 3 );
	printf( "Calling callback() from thread.\n" );
	GCB( GData ); /* crashes here */
	printf( "Calling callback() from thread done.\n" );
	return( NULL );
}

int lib_RegisterWorkDoneCallback( void *a, 
	lib_work_done_callback_t CB, void *Data )
{
	pthread_t thread;
	pthread_attr_t attr;
	int res = 0;
	
	GCB = CB;
	GData = Data;
	
	pthread_attr_init( &attr );
	pthread_attr_setdetachstate( &attr, PTHREAD_CREATE_DETACHED );
	if( pthread_create( &thread, &attr, run, NULL ) ) {
		printf( "Error: Could not create thread.\n" );
		res = 1;
	}
	pthread_attr_destroy( &attr );
	return( res );
}