unlockpt — unlock a pseudoterminal master/slave pair
Synopsis
#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
Description
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.
Return Value
When successful, unlockpt() returns 0. Otherwise, it returns -1 and sets errno appropriately.
Errors
- EBADF
The fd argument is not a file descriptor open for writing.
- EINVAL
The fd argument is not associated with a master pseudoterminal.
Versions
unlockpt() is provided in glibc since version 2.1.
Attributes
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
|---|---|---|
| unlockpt() | Thread safety | MT-Safe |
Conforming to
POSIX.1-2001, POSIX.1-2008.
See Also
Colophon
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Referenced By
getpt(3), grantpt(3), ioctl_tty(2), posix_openpt(3), pts(4), ptsname(3), pty(7).