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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  buf-
       fer  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:


       tab()    allbox;    cw(2.750000i)|     cw(2.750000i)     lw(2.750000i)|
       lw(2.750000i).  ATTRIBUTE TYPEATTRIBUTE VALUE MT-LevelAsync-Signal-Safe


SEE ALSO
       ipcrm(1),    ipcs(1),   intro(2),   semctl(2),   semget(2),   semop(2),
       attributes(5)



SunOS 5.10                        8 Mar 2000                         semids(2)