unlockpt(3) Library Functions Manual unlockpt(3) NAME unlockpt - unlock a pseudoterminal master/slave pair LIBRARY Standard C library (libc, -lc) SYNOPSIS #define _XOPEN_SOURCE #include int unlockpt(int fd); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): unlockpt(): Since glibc 2.24: _XOPEN_SOURCE >= 500 glibc 2.23 and earlier: _XOPEN_SOURCE DESCRIPTION The unlockpt() function unlocks the slave pseudoterminal device corresponding to the master pseudoterminal referred to by the file descriptor fd. unlockpt() should be called before opening the slave side of a pseudoterminal. RETURN VALUE When successful, unlockpt() returns 0. Otherwise, it returns -1 and sets errno to indicate the error. ERRORS EBADF The fd argument is not a file descriptor open for writing. EINVAL The fd argument is not associated with a master pseudoterminal. ATTRIBUTES For an explanation of the terms used in this section, see attributes(7). +--------------------------------------------+---------------+---------+ |Interface | Attribute | Value | +--------------------------------------------+---------------+---------+ |unlockpt () | Thread safety | MT-Safe | +--------------------------------------------+---------------+---------+ STANDARDS POSIX.1-2008. HISTORY glibc 2.1. POSIX.1-2001. SEE ALSO grantpt(3), posix_openpt(3), ptsname(3), pts(4), pty(7) Linux man-pages 6.9.1 2024-05-02 unlockpt(3)