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Microsoft OS/2 SDK 03-01-1988

/*
 * Example of DosExitList usage.
 *
 * Typically, exit list routines are used to free any resources that the
 * process may have owned, and leave any shared resources in a consistent
 * state. Semaphores and shared memory are the common cases. It is not
 * necessary to close files, since the system does that automatically
 * when a process terminates.
 *
 * When a process is in exit list processing, it is already in a
 * half-terminated state, and should be very careful not to cause
 * problems or execute too long.  Specifically, actions such as waiting
 * on semaphores or for other processes to finish are extremely bad
 * ideas.  It is not possible to create new threads or exec another
 * process while in exit list processing.
 *
 * This example shows exit list processing routines being added and removed.
 *
 * Created by Microsoft Corp. 1986, 1987, 1988
 */

#define INCL_DOSPROCESS

#include <os2def.h>
#include <bsedos.h>

void e_handler1();			/* two exit handler routines */
void e_handler2();

void main()
{
	/* add a routine to the termination list */
	DosExitList(EXLST_ADD, e_handler1);
	
	/* add another routine to the termination list */
	DosExitList(EXLST_ADD, e_handler2);

	/* remove a routine from the termination list */
	DosExitList(EXLST_REMOVE, e_handler1);
	
	/* exit this process */
	printf("about to exit\n");
	DosExit(EXIT_PROCESS,0);
}

/* first exit handler, not actually called in this example */
void e_handler1()
{
	/* shared resource cleanup should be done here */
	printf("this is exit handler 1\n");

	/* advance to next handler in exit list (if any) */
	DosExitList(EXLST_EXIT, 0);
}

/* second exit handler - this one is called when the process terminates */
void e_handler2()
{
	/* shared resource cleanup should be done here */
	printf("this is exit handler 2\n");

	/* advance to next handler in exit list (if any) */
	DosExitList(EXLST_EXIT, 0);
}

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