PROLOG

       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

       sys/mman.h — memory management declarations

SYNOPSIS

       #include <sys/mman.h>

DESCRIPTION

       The  <sys/mman.h>  header  shall  define  the  following  symbolic  constants  for  use as
       protection options:

       PROT_EXEC     Page can be executed.

       PROT_NONE     Page cannot be accessed.

       PROT_READ     Page can be read.

       PROT_WRITE    Page can be written.

       The <sys/mman.h> header shall define the following symbolic  constants  for  use  as  flag
       options:

       MAP_FIXED     Interpret addr exactly.

       MAP_PRIVATE   Changes are private.

       MAP_SHARED    Share changes.

       The  <sys/mman.h>  header  shall  define  the following symbolic constants for the msync()
       function:

       MS_ASYNC      Perform asynchronous writes.

       MS_INVALIDATE Invalidate mappings.

       MS_SYNC       Perform synchronous writes.

       The <sys/mman.h> header shall define the following symbolic constants for  the  mlockall()
       function:

       MCL_CURRENT   Lock currently mapped pages.

       MCL_FUTURE    Lock pages that become mapped.

       The  <sys/mman.h>  header  shall  define the symbolic constant MAP_FAILED which shall have
       type void * and shall be used to indicate a failure from the mmap() function .

       If the Advisory Information option is supported,  the  <sys/mman.h>  header  shall  define
       symbolic constants for the advice argument to the posix_madvise() function as follows:

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

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

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

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

       The <sys/mman.h> header shall define the following symbolic constants for use as flags for
       the posix_typed_mem_open() function:

       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  <sys/mman.h>  header shall define the mode_t, off_t, and size_t types as described in
       <sys_types.h>.

       The <sys/mman.h> header shall  define  the  posix_typed_mem_info  structure,  which  shall
       include 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 POSIX.1‐2008,  mlock(),  mlockall(),  mmap(),  mprotect(),
       msync(),   munmap(),   posix_madvise(),   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,  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 .