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mlockall(3)
NAME
  mlockall, munlockall - Locks into memory, or unlocks, all of a specified
  process's pages (P1003.1b)

LIBRARY
  Realtime Library (librt.so, librt.a)

SYNOPSIS
  #include <sys/mman.h>

  int mlockall (
  int flags);

  int munlockall (void);

PARAMETERS
  flags	  Determines whether the pages to be locked are those currently
	  mapped by the process's address space, those that will be mapped in
	  the future, or both. The flags argument is constructed as the OR of
	  one or more of the constants, MCL_CURRENT or MCL_FUTURE, as defined
	  in the <mman.h> header file.

DESCRIPTION
  The mlockall function causes all of the pages mapped by the process's
  address space to be memory resident until unlocked by a call to the
  munlockall function, until the process exits, or until the process calls
  exec.	 MCL_CURRENT locks all of the pages currently mapped into the
  process's address space. MCL_FUTURE locks all of the pages that become
  mapped into the process's address space in the future, when those mappings
  are established. You can specify MCL_CURRENT and subsequently specify
  MCL_FUTURE to lock both current and future address space.

  The munlockall function unlocks all currently mapped pages of the process's
  address space.  Any pages that become mapped into a process's address space
  after a call to munlockall are not locked unless otherwise specified by a
  subsequent call to mlockall. Pages locked or mapped into another process's
  address space are unaffected by this process's call to the munlockall
  function.

  Locking the process's pages into memory also makes the process unswappable.
  When the pages are unlocked, the process is made swappable.

  A lock is not inherited across a fork.  All memory locks established on an
  address by this process are removed if an address range associated with the
  lock is unmapped with a call to the munmap function.

  You must have superuser privileges to call the mlockall function.

RETURN VALUES
  On a successful call to the mlockall function, a value of 0 (zero) is
  returned and memory is locked.  On an unsuccessful call, a value of -1 is
  returned, no memory is locked, and errno is set to indicate that an error
  occurred.

  On a successful call to the munlockall function, a value of 0 (zero) is
  returned and memory is unlocked. On an unsuccessful call, a value of -1 is
  returned and errno is set to indicate that an error occurred.

ERRORS
  The mlockall and munlockall functions fail under the following condition:

  [ENOSYS]	 The implementation does not support this memory locking
		 interface.

  If any of the following conditions occur, the mlockall function fails:

  [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.

  [ENOMEM]	 Locking all of the pages currently mapped into the process's
		 address space exceeds an implementation-defined limit on the
		 amount of memory that the process may lock.

  [EPERM]	 The calling process does not have the appropriate privilege
		 to perform the requested operation.

RELATED INFORMATION
  Functions: exec(2), _exit(2), fork(2), munmap(2)

  Guide to Realtime Programming

Index for Section 3

Alphabetical listing for M

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