unlockpt(3) Library Functions Manual unlockpt(3) unlockpt - / - C (libc, -lc) #define _XOPEN_SOURCE #include int unlockpt(int fd); glibc (. feature_test_macros(7)): unlockpt(): glibc 2.24: _XOPEN_SOURCE >= 500 glibc 2.23 : _XOPEN_SOURCE The unlockpt() function unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by the file descriptor fd. unlockpt() -. When successful, unlockpt() returns 0. Otherwise, it returns -1 and sets errno to indicate the error. EBADF fd , . EINVAL fd -. attributes(7). +----------------------------+----------------------------------------------------------+--------------------------+ | | | | +----------------------------+----------------------------------------------------------+--------------------------+ |unlockpt() | | MT-Safe | +----------------------------+----------------------------------------------------------+--------------------------+ POSIX.1-2008. glibc 2.1. POSIX.1-2001. grantpt(3), posix_openpt(3), ptsname(3), pts(4), pty(7) () Azamat Hackimov , Dmitriy Ovchinnikov , Dmitry Bolkhovskikh , Katrin Kutepova , Yuri Kozlov ; GNU (GNU General Public License - GPL, 3 ) , - . - , , () () () . Linux man-pages 6.18 21 2025 . unlockpt(3)