sys_mman.h(3)              POSIX Programmer's Manual             sys_mman.h(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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(3)
