Cygwin doesn't seem to have POSIX's unfortunately-named "posix_openpt" function in its stdlib.h. The function's documented here:
http://www.opengroup.org/onlinepubs/000095399/functions/posix_openpt.html I'm currently successfully using the implementation below in my application, but wondered if there was any interest in adding it to Cygwin itself? #ifdef __CYGWIN__ // Cygwin doesn't currently have posix_openpt(3). int posix_openpt(int oflag) { return open("/dev/ptmx", oflag); } #endif (Given the simplicity of the implementation, you might be wondering why anyone would care about this trivial little function, other than a standards pedant? The answer is that although that implementation suffices on Cygwin and Linux, OSes such as Darwin require a complicated trawl through /dev looking for suitable candidates.) -- Elliott Hughes, BlueArc Engineering