shm.h

NAME

sys/shm.h -XSI shared memory facility

SYNOPSIS

#include <sys/shm.h>

DESCRIPTION

The <sys/shm.h> header shall define the fllowing symbolic constants:

SHM_RDONLY

Attach read-only(else read_write)

SHM_RND

Round attach address to SHMLBA.

The <sys/shm.h> header shall define the fllowing symbolic value:

SHMLBA

Segment low boundary address multiple.

The fllowing data types shall be defined through typedef:

shmatt_t

Unsigned used for the number of current attaches that must be able to store values at least as large as a type unsigned short.

The shmid_ds structure shall contain the fo;llowing 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 pid_t, time_t, key_t, and size_t types shall be defined as described in <sys/types.h>

The following shall be declared as functions and also be defined as macros. Function prototypes shall be provided.

vopid *shmat(int, const coid *, int);

int shmctl(int, int, struct shmid_ds *);

int shmdt(const coid *);

int shmget(key_t, size_t, int);

In addition, all of the symbols from < sys/ipc.h> shall be defined when this header is included.

The following sections arenformative.

APPLICATION USAGE

None.

RATIONALE

None.

SEE ALSO

<sys/ipc.h>, <sys/types.h>, the System Interfaces volume of IEEE Stf 1003.1-2001, shmat(), shmctl(), shmdt(), shmget().