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sys/mman.h - memory management declarations
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:
Page can be read.
Page can be written.
Page can be executed.
Page cannot be accessed.
The following flag options shall be defined:
Changes are private.
Interpret addr exactly.
The following flags shall be defined for msync():
Perform asynchronous writes.
Perform synchronous writes.
The following symbolic constants shall be defined for the mlockall()
Lock currently mapped pages.
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:
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
sequentially from lower addresses to higher addresses.
The application expects to access the specified range in a
The application expects to access the specified range in the
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():
Allocate on mmap().
Allocate contiguously on mmap().
Map on mmap(), without affecting allocatability.
The mode_t, off_t, and size_t types shall be defined as described in
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);
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.
<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()
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 .