sys_mman.h

<sys/mman.h>(P)						      <sys/mman.h>(P)



NAME
       sys/mman.h - memory management declarations

SYNOPSIS
       #include <sys/mman.h>

DESCRIPTION
       The  <sys/mman.h> header shall be supported if the implementation sup-
       ports at least one of the following options:

	* The Memory Mapped Files option


	* The Shared Memory Objects option


	* The Process Memory Locking option


	* The Memory Protection option


	* The Typed Memory Objects option


	* The Synchronized Input and Output option


	* The Advisory Information option


	* The Typed Memory Objects option


       If one or more of the Advisory Information, Memory  Mapped  Files,  or
       Shared  Memory Objects options are supported, the following protection
       options shall be defined:

       PROT_READ
	      Page can be read.

       PROT_WRITE
	      Page can be written.

       PROT_EXEC
	      Page can be executed.

       PROT_NONE
	      Page cannot be accessed.


       The following flag options shall be defined:

       MAP_SHARED
	      Share changes.

       MAP_PRIVATE
	      Changes are private.

       MAP_FIXED
	      Interpret addr exactly.


       The following flags shall be defined for msync():

       MS_ASYNC
	      Perform asynchronous writes.

       MS_SYNC
	      Perform synchronous writes.

       MS_INVALIDATE
	      Invalidate mappings.


       The following symbolic constants shall be defined for  the  mlockall()
       function:

       MCL_CURRENT
	      Lock currently mapped pages.

       MCL_FUTURE
	      Lock pages that become mapped.


       The  symbolic constant MAP_FAILED shall be defined to indicate a fail-
       ure from the mmap() function.

       If the Advisory Information and either  the  Memory  Mapped  Files  or
       Shared Memory Objects options are supported, values for advice used by
       posix_madvise() shall be defined as follows:

       POSIX_MADV_NORMAL

	      The application has no advice to	give  on  its  behavior	 with
	      respect  to the specified range. It is the default characteris-
	      tic if no advice is given for a range of memory.

       POSIX_MADV_SEQUENTIAL

	      The application expects to access the specified  range  sequen-
	      tially from lower addresses to higher addresses.

       POSIX_MADV_RANDOM

	      The application expects to access the specified range in a ran-
	      dom order.

       POSIX_MADV_WILLNEED

	      The application expects to access the specified  range  in  the
	      near future.

       POSIX_MADV_DONTNEED

	      The  application	expects that it will not access the specified
	      range in the near future.


       The following flags shall be defined for posix_typed_mem_open():

       POSIX_TYPED_MEM_ALLOCATE

	      Allocate on mmap().

       POSIX_TYPED_MEM_ALLOCATE_CONTIG

	      Allocate contiguously on mmap().

       POSIX_TYPED_MEM_MAP_ALLOCATABLE

	      Map on mmap(), without affecting allocatability.


       The mode_t, off_t, and size_t types shall be defined as	described  in
       <sys/types.h> .

       The     <sys/mman.h>	header	  shall	   define    the    structure
       posix_typed_mem_info, which includes at least the following member:


	      size_t  posix_tmi_length	Maximum length which may be allocated
					from a typed memory object.

       The following shall be declared as functions and may also  be  defined
       as macros. Function prototypes shall be provided.


	      int    mlock(const void *, size_t);


	      int    mlockall(int);


	      void  *mmap(void *, size_t, int, int, int, off_t);


	      int    mprotect(void *, size_t, int);


	      int    msync(void *, size_t, int);


	      int    munlock(const void *, size_t);


	      int    munlockall(void);


	      int    munmap(void *, size_t);


	      int    posix_madvise(void *, size_t, int);


	      int    posix_mem_offset(const void *restrict, size_t, off_t *restrict,
			 size_t *restrict, int *restrict);
	      int    posix_typed_mem_get_info(int, struct posix_typed_mem_info *);
	      int    posix_typed_mem_open(const char *, int, int);


	      int    shm_open(const char *, int, mode_t);
	      int    shm_unlink(const char *);


       The following sections are informative.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       <sys/types.h>  , the System Interfaces volume of IEEE Std 1003.1-2001,
       mlock(), mlockall(), mmap(), mprotect(), msync(), munlock(),  munlock-
       all(),	munmap(),   posix_mem_offset(),	  posix_typed_mem_get_info(),
       posix_typed_mem_open(), shm_open(), shm_unlink()

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic	 form
       from  IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface  (POSIX),  The  Open	Group
       Base  Specifications Issue 6, Copyright (C) 2001-2003 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 http://www.opengroup.org/unix/online.html .



POSIX				     2003		      <sys/mman.h>(P)