@node _dos_lock, dos
@findex _dos_lock
@subheading Syntax

@example
#include <io.h>

int _dos_lock(int fd, long offset, long length);
@end example

@subheading Description

Adds an advisory lock to the specified region of the file.

@subheading Return Value

Zero if the lock was added, nonzero otherwise.

@subheading Portability

@portability !ansi, !posix