@ignore
 * File llseek.txh.
 *
 * Copyright (C) 2000 Martin Str@"omberg <ams@ludd.luth.se>.
 *
 * This software may be used freely so long as this copyright notice is
 * left intact. There is no warranty on this software.
 *
@end ignore

@node llseek, io
@findex llseek
@subheading Syntax

@example
#include <unistd.h>

offset_t llseek(int fd, offset_t offset, int whence);
@end example

@subheading Description

This function moves the file pointer for @var{fd} according to
@var{whence}:

@table @code

@item SEEK_SET

The file pointer is moved to the offset specified.

@item SEEK_CUR

The file pointer is moved relative to its current position.

@item SEEK_END

The file pointer is moved to a position @var{offset} bytes from the end
of the file.  The offset is usually nonpositive in this case. 

@end table

@var{offset} is of type long long, thus enabling you to seek with
offsets as large as ~2^63 (FAT16 limits this to ~2^31; FAT32 limits
this to 2^32-2).

@subheading Return Value

The new offset is returned. Note that due to limitations in the
underlying DOS implementation the offset wraps around to 0 at offset
2^32. -1 means the call failed.

@subheading Portability

@portability !ansi, !posix

@subheading Example

@example
long long ret;

ret = llseek(fd, (1<<32), SEEK_SET); /* Now ret equals 0
                                      * (unfortunately). */
ret = llseek(fd, -1, SEEK_CUR); /* Now ret equals 2^32-1 (good!). */
ret = llseek(fd, 0, SEEK_SET); /* Now ret equals 0 (good!). */
ret = llseek(fd, -1, SEEK_CUR); /* Now ret equals 2^32-1 (bad). */
@end example