sys_mman.h(7POSIX) POSIX Programmer's Manual sys_mman.h(7POSIX)
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.
sys/mman.h — memory management declarations
The <sys/mman.h> header shall define the following symbolic constants for use as protec‐
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
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()
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()
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 sym‐
bolic constants for the advice argument to the posix_madvise() function as follows:
The application expects that it will not access the specified range in the near
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.
The application expects to access the specified range in a random order.
The application expects to access the specified range sequentially from lower
addresses to higher addresses.
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:
Allocate on mmap().
Allocate contiguously on mmap().
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
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);
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 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.
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()
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 discrep‐
ancy 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 .
IEEE/The Open Group 2013 sys_mman.h(7POSIX)