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(),  munlockall(),  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 Technology -- 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 .