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 ||
(_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED)
Glibc 2.23 and earlier:
_XOPEN_SOURCE
The
unlockpt() function unlocks the slave pseudoterminal device
corresponding to the master pseudoterminal referred to by
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 appropriately.
- 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).
| Interface |
Attribute |
Value |
| unlockpt () |
Thread safety |
MT-Safe |
POSIX.1-2001, POSIX.1-2008.
grantpt(3),
posix_openpt(3),
ptsname(3),
pts(4),
pty(7)