Provided by: manpages-dev_5.10-1ubuntu1_all 
NAME
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 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 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
grantpt(3), posix_openpt(3), ptsname(3), pts(4), pty(7)
COLOPHON
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information about reporting bugs, and the latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2017-07-13 UNLOCKPT(3)