Manpages - unlockpt.3

unlockpt - unlock a pseudoterminal master/slave pair

  #define _XOPEN_SOURCE
  #include <stdlib.h>

  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

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.

When successful, *unlockpt*() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.

EBADF

The fd argument is not a file descriptor open for writing.

EINVAL

The fd argument is not associated with a master pseudoterminal.

*unlockpt*() is provided in glibc since version 2.1.

For an explanation of the terms used in this section, see *attributes*(7).

POSIX.1-2001, POSIX.1-2008.

*grantpt*(3), *posix_openpt*(3), *ptsname*(3), *pts*(4), *pty*(7)

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