NAME
posix_fadvise —
hint at the future access pattern of a
file
LIBRARY
library “libc”
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
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.