sys_shm.h(0p) — Linux manual page


sys_shm.h(0P)           POSIX Programmer's Manual          sys_shm.h(0P)

PROLOG         top

       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         top

       sys/shm.h — XSI shared memory facility

SYNOPSIS         top

       #include <sys/shm.h>

DESCRIPTION         top

       The <sys/shm.h> header shall define the following symbolic

       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>

       The following sections are informative.



RATIONALE         top




SEE ALSO         top

       sys_ipc.h(0p), sys_types.h(0p)

       The System Interfaces volume of POSIX.1‐2017, shmat(3p),
       shmctl(3p), shmdt(3p), shmget(3p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see .

IEEE/The Open Group               2017                     sys_shm.h(0P)

Pages that refer to this page: shmat(3p)shmctl(3p)shmdt(3p)shmget(3p)