shm_unlink()

Remove the name of a shared memory object

Synopsis:

#include <sys/mman.h>

int shm_unlink( const char * name );

Arguments:

name: The name of the shared memory object that you want to remove.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The shm_unlink() function removes the name of the shared memory object specified by name. After removing the name, you can't use shm_open() to access the object.

This function doesn't affect any references to the shared memory object (i.e., file descriptors or memory mappings). The reference count is on the underlying object; there's no reference count on the name. The name counts as one of the references, so the reference count is decremented by this function, but the shared memory isn't actually deleted until you remove all open and mmap references to it.

Returns:

0: Success.
-1: An error occurred (errno is set).

Errors:

EACCES: Permission to unlink the shared memory object is denied.
ELOOP: Too many levels of symbolic links or prefixes.
ENAMETOOLONG: The length of the name argument exceeds PATH_MAX.
ENOENT: The named shared memory object doesn't exist, or the name argument points to an empty string.
ENOSYS: The shm_unlink() function isn't supported by this implementation.

Examples:

See shm_open().

Classification:

POSIX 1003.1 SHM

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	Yes
Thread	Yes