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Manuál Linux
[Linux manuál]

shm_unlink: odebrat objekt sdílené paměti (REÁLNÝ ČAS)

Originální popis anglicky: shm_unlink - remove a shared memory object ( REALTIME)

Návod, kniha: POSIX Programmer's Manual

STRUČNĚ

#include <sys/mman.h>
 
 
int shm_unlink(const char * name);
 

POPIS / INSTRUKCE

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).

NÁVRATOVÁ HODNOTA

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.

CHYBY / ERRORY

The shm_unlink() function shall fail if:
EACCES
Permission is denied to unlink the named shared memory object.
ENAMETOOLONG
The length of the name argument exceeds {PATH_MAX} or a pathname component is longer than {NAME_MAX}.
ENOENT
The named shared memory object does not exist.
 
The following sections are informative.

PŘÍKLADY POUŽITÍ

None.

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.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SOUVISEJÍCÍ

close() , mmap() , munmap() , shmat() , shmctl() , shmdt() , shm_open() , the Base Definitions volume of IEEE Std 1003.1-2001, <sys/mman.h> Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
2003 IEEE/The Open Group
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