sys/shm.h - XSI shared memory facility
[XSI] #include <sys/shm.h>
The <sys/shm.h> header shall define the following symbolic constants:
- Attach read-only (else read-write).
- Round attach address to SHMLBA.
- Segment low boundary address multiple.
The <sys/shm.h> header shall define the following data types through typedef:
- 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.
XSH shmat, shmctl, shmdt, shmget
First released in Issue 2. Derived from System V Release 2.0.
The type of shm_segsz is changed from int to size_t.
Austin Group Interpretation 1003.1-2001 #179 is applied.
This reference page is clarified with respect to macros and symbolic constants.
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