lockf
=====

POSIX specification:
 https://pubs.opengroup.org/onlinepubs/9699919799/functions/lockf.html

Gnulib module: ---

Portability problems fixed by Gnulib:

  * On platforms where off_t is a 32-bit type, this function may not work correctly across the entire data range of files 2 GiB and larger. See Large File Support.

Portability problems not fixed by Gnulib:

  * This function is missing on some platforms: Minix 3.1.8, Cygwin 1.5.x, mingw, MSVC 14, Android 6.0.