February 20, 2006 POSIX_FADVISE 2

### NAME

posix_fadvise - hint at the future access pattern of a file

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```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 followings.

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

```POSIX_FADV_WILLNEED`, ```POSIX_FADV_DONTNEED`, and ```POSIX_FADV_NOREUSE` are not implemented.

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.