sys_shm.h (0p)

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.
 

NAME

sys/shm.h — XSI shared memory facility

SYNOPSIS

#include <sys/shm.h>

DESCRIPTION

The <sys/shm.h> header shall define the following symbolic constants:
SHM_RDONLY
Attach read-only (else read-write).
SHM_RND
Round attach address to SHMLBA.
SHMLBA
Segment low boundary address multiple.
The <sys/shm.h> header shall define the following data types through typedef:
shmatt_t
Unsigned integer used for the number of current attaches that must be able to store values at least as large as a type unsigned short.
The <sys/shm.h> header shall define the shmid_ds structure, which shall include the following members:
 

struct ipc_perm shm_perm Operation permission structure.
size_t shm_segsz Size of segment in bytes.
pid_t shm_lpid Process ID of last shared memory operation.
pid_t shm_cpid Process ID of creator.
shmatt_t shm_nattch Number of current attaches.
time_t shm_atime Time of last shmat().
time_t shm_dtime Time of last shmdt().
time_t shm_ctime Time of last change by shmctl().
The <sys/shm.h> header shall define the pid_t, size_t, and time_t types as described in <sys/types.h>.
The following shall be declared as functions and may also be defined as macros. Function prototypes shall be provided.
 

void *shmat(int, const void *, int);
int shmctl(int, int, struct shmid_ds *);
int shmdt(const void *);
int shmget(key_t, size_t, int);
In addition, the <sys/shm.h> header shall include the <sys/ipc.h> header.
The following sections are informative.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

<sys_ipc.h>, <sys_types.h>
The System Interfaces volume of POSIX.1‐2008, shmat(), shmctl(), shmdt(), shmget()

Information

Source
POSIX
OS/version
IEEE/The Open Group
Source updated
January 1, 2013
Page created
March 3, 2018
Page generated
March 4, 2018