NAME lockf - apply, test or remove a POSIX lock on an open file LIBRARY Standard ... library ( libc , -lc ) SYNOPSIS #include int lockf(int fd , int op , off_t len ); Featuredone by functions like flock (2) and lockf (3).) All this is invisibledone by functions like flock (2) and lockf (3).) All this is invisibledone by functions like flock (2) and lockf (3).) All this is invisible