NAME
posix_fadvise —
hint at the future
access pattern of a file
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <fcntl.h>
int
posix_fadvise(
int
fd,
off_t offset,
off_t size,
int hint);
DESCRIPTION
posix_fadvise() hints at the application's access pattern to
the file and range given by the file descriptor,
fd, and
offset and
size. If
size is zero, it means to the end of file.
hint should be one of the following:
- POSIX_FADV_NORMAL
- No hint. (default)
- POSIX_FADV_RANDOM
- Random access.
- POSIX_FADV_SEQUENTIAL
- Sequential access. (from lower offset to higher
offset.)
- POSIX_FADV_WILLNEED
- Will be accessed.
- POSIX_FADV_DONTNEED
- Will not be accessed.
- POSIX_FADV_NOREUSE
- Will be accessed just once.
Calling
posix_fadvise() doesn't alter the semantics of the
operations, it is only a matter of performance.
RETURN VALUES
On success,
posix_fadvise() returns 0. Otherwise, it returns
an error number.
SEE ALSO
errno(2),
madvise(2)
BUGS
For
POSIX_FADV_NORMAL
,
POSIX_FADV_RANDOM
, and
POSIX_FADV_SEQUENTIAL
, the current implementation
ignores
offset and
size, and
applies the hint to the whole file.