PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

MLOCKALL(3P)              POSIX Programmer's Manual             MLOCKALL(3P)

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

       mlockall, munlockall — lock/unlock the address space of a process
       (REALTIME)

SYNOPSIS         top

       #include <sys/mman.h>

       int mlockall(int flags);
       int munlockall(void);

DESCRIPTION         top

       The mlockall() function shall cause all of the pages mapped by the
       address space of a process to be memory-resident until unlocked or
       until the process exits or execs another process image. The flags
       argument determines whether the pages to be locked are those
       currently mapped by the address space of the process, those that are
       mapped in the future, or both. The flags argument is constructed from
       the bitwise-inclusive OR of one or more of the following symbolic
       constants, defined in <sys/mman.h>:

       MCL_CURRENT Lock all of the pages currently mapped into the address
                   space of the process.

       MCL_FUTURE  Lock all of the pages that become mapped into the address
                   space of the process in the future, when those mappings
                   are established.

       If MCL_FUTURE is specified, and the automatic locking of future
       mappings eventually causes the amount of locked memory to exceed the
       amount of available physical memory or any other implementation-
       defined limit, the behavior is implementation-defined. The manner in
       which the implementation informs the application of these situations
       is also implementation-defined.

       The munlockall() function shall unlock all currently mapped pages of
       the address space of the process. Any pages that become mapped into
       the address space of the process after a call to munlockall() shall
       not be locked, unless there is an intervening call to mlockall()
       specifying MCL_FUTURE or a subsequent call to mlockall() specifying
       MCL_CURRENT. If pages mapped into the address space of the process
       are also mapped into the address spaces of other processes and are
       locked by those processes, the locks established by the other
       processes shall be unaffected by a call by this process to
       munlockall().

       Upon successful return from the mlockall() function that specifies
       MCL_CURRENT, all currently mapped pages of the address space of the
       process shall be memory-resident and locked.  Upon return from the
       munlockall() function, all currently mapped pages of the address
       space of the process shall be unlocked with respect to the address
       space of the process.  The memory residency of unlocked pages is
       unspecified.

       Appropriate privileges are required to lock process memory with
       mlockall().

RETURN VALUE         top

       Upon successful completion, the mlockall() function shall return a
       value of zero. Otherwise, no additional memory shall be locked, and
       the function shall return a value of −1 and set errno to indicate the
       error. The effect of failure of mlockall() on previously existing
       locks in the address space is unspecified.

       If it is supported by the implementation, the munlockall() function
       shall always return a value of zero. Otherwise, the function shall
       return a value of −1 and set errno to indicate the error.

ERRORS         top

       The mlockall() function shall fail if:

       EAGAIN Some or all of the memory identified by the operation could
              not be locked when the call was made.

       EINVAL The flags argument is zero, or includes unimplemented flags.

       The mlockall() function may fail if:

       ENOMEM Locking all of the pages currently mapped into the address
              space of the process would exceed an implementation-defined
              limit on the amount of memory that the process may lock.

       EPERM  The calling process does not have appropriate privileges to
              perform the requested operation.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       exec(1p), exit(3p), fork(3p), mlock(3p), munmap(3p)

       The Base Definitions volume of POSIX.1‐2008, sys_mman.h(0p)

COPYRIGHT         top

       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 .

IEEE/The Open Group                 2013                        MLOCKALL(3P)

Pages that refer to this page: sys_mman.h(0p)_Exit(3p)mlock(3p)munlockall(3p)munmap(3p)