semids(2)							   System Calls 							 semids(2)

NAME

       semids - discover all semaphore identifiers

SYNOPSIS

       #include <sys/sem.h>

       int semids(int *buf, uint_t nids, uint_t *pnids);

DESCRIPTION

       The  semids() function copies all active semaphore identifiers from the system into the user-defined buffer specified by buf, provided that
       the number of such identifiers is not greater than the number of integers the buffer can contain, as specified by nids.	If the size of the
       buffer is insufficient to contain all of the active semaphore identifiers in the system, none are copied.

       Whether	or  not  the  size of the buffer is sufficient to contain all of them, the number of active semaphore identifiers in the system is
       copied into the unsigned integer pointed to by pnids.

       If nids is 0 or less than the number of active semaphore identifiers in the system, buf is ignored.

RETURN VALUES

       Upon successful completion, semids() returns 0.	Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The semids() function will fail if:

       EFAULT	 The buf or pnids argument points to an illegal address.

USAGE

       The semids() function returns a snapshot of all the active semaphore identifiers in the system.	More may be added and some may be  removed
       before they can be used by the caller.

EXAMPLES

       Example 1 semids() example

       This is sample C code indicating how to use the semids() function.

	 void
	 examine_semids()
	 {
	      int *ids = NULL;
	      uint_t nids = 0;
	      uint_t n;
	      int i;

	      for (;;) {
		   if (semids(ids, nids, &n) != 0) {
			perror("semids");
			exit(1);
		   }
		   if (n <= nids)     /* we got them all */
			break;
		   /* we need a bigger buffer */
		   ids = realloc(ids, (nids = n) * sizeof (int));
	      }

	      for (i = 0; i < n; i++)
		   process_semid(ids[i]);

	      free(ids);
	 }

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ipcrm(1), ipcs(1), Intro(2), semctl(2), semget(2), semop(2), attributes(5)

SunOS 5.11							    8 Mar 2000								 semids(2)