opendarwin man page for shmget

Query: shmget

OS: opendarwin

Section: 2

Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar

SHMGET(2)						      BSD System Calls Manual							 SHMGET(2)

NAME
shmget -- get shared memory area identifier
SYNOPSIS
#include <sys/types.h> #include <sys/ipc.h> #include <sys/shm.h> int shmget(key_t key, int size, int shmflg);
DESCRIPTION
shmget() returns the shared memory identifier associated with the key key. A shared memory segment is created if either key is equal to IPC_PRIVATE, or key does not have a shared memory segment identifier associated with it, and the IPC_CREAT bit is set in shmflg. If a new shared memory segment is created, the data structure associated with it (the shmid_ds structure, see shmctl(2)) is initialized as follows: o shm_perm.cuid and shm_perm.uid are set to the effective uid of the calling process. o shm_perm.gid and shm_perm.cgid are set to the effective gid of the calling process. o shm_perm.mode is set to the lower 9 bits of shmflg. o shm_lpid, shm_nattch, shm_atime, and shm_dtime are set to 0 o shm_ctime is set to the current time. o shm_segsz is set to the value of size.
RETURN VALUES
Upon successful completion a positive shared memory segment identifier is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.
ERRORS
[EACESS] A shared memory segment is already associated with key and the caller has no permission to access it. [EEXIST] Both IPC_CREAT and IPC_EXCL are set in shmflg, and a shared memory segment is already associated with key. [ENOSPC] A new shared memory indentifier could not be created because the system limit for the number of shared memory identifiers has been reached. [ENOENT] IPC_CREAT was not set in shmflg and no shared memory segment associated with key was found. [ENOMEM] There is not enough memory left to created a shared memory segment of the requested size.
SEE ALSO
shmctl(2), shmat(2), shmdt(2)
BSD
August 17, 1995 BSD
Related Man Pages
shmget(2) - opensolaris
shmget(3) - linux
shmget(2) - opendarwin
shmget(3p) - suse
shmget(3p) - x11r4
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