sys_mman.h(0P)		   POSIX Programmer's Manual		sys_mman.h(0P)

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.1‐2017, 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 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       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 .

IEEE/The Open Group		     2017			sys_mman.h(0P)