man3/unlockpt.3

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   4 .TH UNLOCKPT 3 2008-06-14 "" "Linux Programmer's Manual"
   5 .SH NAME
   6 unlockpt \- unlock a psuedoterminal master/slave pair
   7 .SH SYNOPSIS
   8 .nf
   9 .B #define _XOPEN_SOURCE
  10 .br
  11 .B #include <stdlib.h>
  12 .sp
  13 .BI "int unlockpt(int " fd ");"
  14 .fi
  15 .SH DESCRIPTION
  16 The
  17 .BR unlockpt ()
  18 function unlocks the slave psuedoterminal device
  19 corresponding to the master psuedoterminal referred to by
  20 .IR fd .
  21 .PP
  22 .BR unlockpt ()
  23 should be called before opening the slave side of a psuedoterminal.
  24 .SH "RETURN VALUE"
  25 When successful,
  26 .BR unlockpt ()
  27 returns 0.
  28 Otherwise, it returns \-1 and sets
  29 .I errno
  30 appropriately.
  31 .SH ERRORS
  32 .TP
  33 .B EBADF
  34 The
  35 .I fd
  36 argument is not a file descriptor open for writing.
  37 .TP
  38 .B EINVAL
  39 The
  40 .I fd
  41 argument is not associated with a master psuedoterminal.
  42 .SH VERSIONS
  43 .BR unlockpt ()
  44 is provided in glibc since version 2.1.
  45 .SH "CONFORMING TO"
  46 POSIX.1-2001.
  47 .SH "SEE ALSO"
  48 .BR grantpt (3),
  49 .BR posix_openpt (3),
  50 .BR ptsname (3),
  51 .BR pts (4),
  52 .BR feature_test_macros (7),
  53 .BR pty (7)