unlockpt(3) — Linux manual page

unlockpt(3)              Library Functions Manual             unlockpt(3)

NAME         top

       unlockpt - unlock a pseudoterminal master/slave pair

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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         top

       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         top

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

ERRORS         top

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

       EINVAL The fd argument is not associated with a master
              pseudoterminal.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌──────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                            │ Attribute     │ Value   │
       ├──────────────────────────────────────┼───────────────┼─────────┤
       │ unlockpt()                           │ Thread safety │ MT-Safe │
       └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS         top

       POSIX.1-2008.

HISTORY         top

       glibc 2.1.  POSIX.1-2001.

SEE ALSO         top

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

COLOPHON         top

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Linux man-pages 6.15            2024-07-23                    unlockpt(3)

Pages that refer to this page: TIOCPKT(2const),  getpt(3),  grantpt(3),  posix_openpt(3),  ptsname(3),  pts(4),  pty(7)

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