<sys/mman.h>(P) 					     POSIX Programmer's Manual						   <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 supports 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 failure 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 characteristic if no
	      advice is given for a range of memory.

       POSIX_MADV_SEQUENTIAL

	      The application expects to access the specified range sequentially from lower addresses to higher addresses.

       POSIX_MADV_RANDOM

	      The application expects to access the specified range in a random 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 .

IEEE
/The Open Group						       2003							   <sys/mman.h>(P)