Missing two lines from <sys/unistd.h>: int _EXFUN(truncate, (int fd, size_t length)); unsigned _EXFUN(usleep, (unsigned int _useconds )); If you add the lines, then programs referencing the functions will link. - For help on using this list (especially unsubscribing), send a message to "gnu-win32-request@cygnus.com" with one line of text: "help".