xenial (7) sys_shm.h.7posix.gz

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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()


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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
       http://www.unix.org/online.html .

       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
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .