shmids(2) System Calls shmids(2)NAMEshmids - 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:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Async-Signal-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOipcrm(1), ipcs(1), intro(2), shmctl(2), shmget(2), shmop(2),
attributes(5)SunOS 5.10 8 Mar 2000 shmids(2)
