POSIX_MAPPED_FILES

POSIX Mapped Files option group. More...

Macros
#define	PROT_NONE   0x0
	Pages may not be accessed.
#define	PROT_READ   0x1
	Pages may be read.
#define	PROT_WRITE   0x2
	Pages may be written.
#define	PROT_EXEC   0x4
	Pages may be executed.
#define	MAP_SHARED   0x1
	Changes are shared between all mappings of the same object.
#define	MAP_PRIVATE   0x2
	Changes are private (copy-on-write).
#define	MAP_FIXED   0x4
	Map at the exact address given in addr.
#define	MAP_ANONYMOUS   0x20
	Anonymous mapping; fd argument is ignored.
#define	MS_SYNC   0x0
	Flush modified pages to the underlying file synchronously.
#define	MS_ASYNC   0x1
	Schedule writes; return immediately.
#define	MS_INVALIDATE   0x2
	Invalidate cached data so subsequent reads reflect the file.
#define	MAP_FAILED   ((void *)-1)
	Value returned by mmap() on failure.

Functions
void *	mmap (void *addr, size_t len, int prot, int flags, int fildes, off_t off)
	Map a file or device into memory.
int	msync (void *addr, size_t length, int flags)
	Synchronise a memory mapping with the underlying storage.
int	munmap (void *addr, size_t len)
	Unmap a previously mapped region.

Detailed Description

POSIX Mapped Files option group.

Macro Definition Documentation

MAP_ANONYMOUS

#define MAP_ANONYMOUS   0x20

Anonymous mapping; fd argument is ignored.

Definition at line 41 of file mman.h.

MAP_FAILED

#define MAP_FAILED   ((void *)-1)

Value returned by mmap() on failure.

Definition at line 51 of file mman.h.

MAP_FIXED

#define MAP_FIXED   0x4

Map at the exact address given in addr.

Definition at line 38 of file mman.h.

MAP_PRIVATE

#define MAP_PRIVATE   0x2

Changes are private (copy-on-write).

Definition at line 36 of file mman.h.

MAP_SHARED

#define MAP_SHARED   0x1

Changes are shared between all mappings of the same object.

Definition at line 34 of file mman.h.

MS_ASYNC

#define MS_ASYNC   0x1

Schedule writes; return immediately.

Definition at line 46 of file mman.h.

MS_INVALIDATE

#define MS_INVALIDATE   0x2

Invalidate cached data so subsequent reads reflect the file.

Definition at line 48 of file mman.h.

MS_SYNC

#define MS_SYNC   0x0

Flush modified pages to the underlying file synchronously.

Definition at line 44 of file mman.h.

PROT_EXEC

#define PROT_EXEC   0x4

Pages may be executed.

Definition at line 31 of file mman.h.

PROT_NONE

#define PROT_NONE   0x0

Pages may not be accessed.

Definition at line 25 of file mman.h.

PROT_READ

#define PROT_READ   0x1

Pages may be read.

Definition at line 27 of file mman.h.

PROT_WRITE

#define PROT_WRITE   0x2

Pages may be written.

Definition at line 29 of file mman.h.

Function Documentation

mmap()

void * mmap	(	void *	addr,
		size_t	len,
		int	prot,
		int	flags,
		int	fildes,
		off_t	off
	)

Map a file or device into memory.

Parameters

addr	Suggested address (hint), or NULL.
len	Length of the mapping in bytes.
prot	Memory protection (PROT_* flags).
flags	Mapping type and options (MAP_* flags).
fildes	File descriptor (-1 for anonymous mappings).
off	Offset within the file (must be page-aligned).

Returns

Base address of the mapping, or MAP_FAILED on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html

msync()

int msync	(	void *	addr,
		size_t	length,
		int	flags
	)

Synchronise a memory mapping with the underlying storage.

Parameters

addr	Base address of the region (must be page-aligned).
length	Length of the region in bytes.
flags	MS_SYNC, MS_ASYNC, or MS_INVALIDATE.

Returns

0 on success, or -1 with errno set on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/msync.html

munmap()

int munmap	(	void *	addr,
		size_t	len
	)

Unmap a previously mapped region.

Parameters

addr	Base address of the mapping.
len	Length of the region in bytes.

Returns

0 on success, or -1 with errno set on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/munmap.html