удалить объект общей памяти (REALTIME) (remove a shared memory object (REALTIME))
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
shm_unlink — remove a shared memory object (REALTIME)
Синопсис (Synopsis)
#include <sys/mman.h>
int shm_unlink(const char *name);
Описание (Description)
The shm_unlink() function shall remove the name of the shared
memory object named by the string pointed to by name.
If one or more references to the shared memory object exist when
the object is unlinked, the name shall be removed before
shm_unlink() returns, but the removal of the memory object
contents shall be postponed until all open and map references to
the shared memory object have been removed.
Even if the object continues to exist after the last
shm_unlink(), reuse of the name shall subsequently cause
shm_open() to behave as if no shared memory object of this name
exists (that is, shm_open() will fail if O_CREAT is not set, or
will create a new shared memory object if O_CREAT is set).
Возвращаемое значение (Return value)
Upon successful completion, a value of zero shall be returned.
Otherwise, a value of -1 shall be returned and errno set to
indicate the error. If -1 is returned, the named shared memory
object shall not be changed by this function call.
Ошибки (Error)
The shm_unlink() function shall fail if:
EACCES Permission is denied to unlink the named shared memory
object.
ENOENT The named shared memory object does not exist.
The shm_unlink() function may fail if:
ENAMETOOLONG
The length of the name argument exceeds {_POSIX_PATH_MAX}
on systems that do not support the XSI option or exceeds
{_XOPEN_PATH_MAX} on XSI systems, or has a pathname
component that is longer than {_POSIX_NAME_MAX} on systems
that do not support the XSI option or longer than
{_XOPEN_NAME_MAX} on XSI systems. A call to shm_unlink()
with a name argument that contains the same shared memory
object name as was previously used in a successful
shm_open() call shall not give an [ENAMETOOLONG] error.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
Names of memory objects that were allocated with open() are
deleted with unlink() in the usual fashion. Names of memory
objects that were allocated with shm_open() are deleted with
shm_unlink(). Note that the actual memory object is not
destroyed until the last close and unmap on it have occurred if
it was already in use.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
A future version might require the shm_open() and shm_unlink()
functions to have semantics similar to normal file system
operations.
Смотри также (See also)
close(3p), mmap(3p), munmap(3p), shmat(3p), shmctl(3p),
shmdt(3p), shm_open(3p)
The Base Definitions volume of POSIX.1‐2017, sys_mman.h(0p)
