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shmids(2)                        System Calls                        shmids(2)



NAME
       shmids - discover all shared memory identifiers

SYNOPSIS
       #include <sys/shm.h>

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

DESCRIPTION
       The  shmids() function copies all active shared memory 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 inte-
       gers the buffer can contain, as specified by nids.  If the size of  the
       buffer is insufficient to contain all of the active shared memory iden-
       tifiers 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 shared memory 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  shared  memory  identi-
       fiers in the system, buf is ignored.

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

ERRORS
       The shmids() function will fail if:

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



USAGE
       The shmids() function returns a snapshot of all the active shared  mem-
       ory  identifiers  in  the  system.   More  may be added and some may be
       removed before they can be used by the caller.

EXAMPLES
       Example 1: shmids() example

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

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

            for (;;) {
                 if (shmids(ids, nids, &n) != 0) {
                      perror("shmids");
                      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_shmid(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),   shmctl(2),   shmget(2),   shmop(2),
       attributes(5)



SunOS 5.10                        8 Mar 2000                         shmids(2)