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 <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
DESCRIPTION
The unlockpt() function unlocks the slave pseudoterminal device corre-
sponding to the master pseudoterminal referred to by the file descrip-
tor 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 attrib-
utes(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 6.7 2023-10-31 unlockpt(3)
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