man3/getpt.3

   1 .\" This man page was written by Jeremy Phelps <jphelps@notreached.net>.
   2 .\"
   3 .\" %%%LICENSE_START(FREELY_REDISTRIBUTABLE)
   4 .\" Redistribute and modify at will.
   5 .\" %%%LICENSE_END
   6 .\"
   7 .TH GETPT 3 2015-03-02 "GNU" "Linux Programmer's Manual"
   8 .SH NAME
   9 getpt \- open the pseudoterminal master (PTM)
  10 .SH SYNOPSIS
  11 .nf
  12 .BR "#define _GNU_SOURCE" "             /* See feature_test_macros(7) */"
  13 .B #include <stdlib.h>
  14 .sp
  15 .B "int getpt(void);"
  16 .fi
  17 .SH DESCRIPTION
  18 .BR getpt ()
  19 opens a pseudoterminal master and returns its file descriptor.
  20 It is equivalent to
  21 .nf
  22
  23     open(/dev/ptmx, O_RDWR | O_NOCTTY);
  24
  25 .fi
  26 on Linux systems, though the pseudoterminal master is located
  27 elsewhere on some systems that use GNU Libc.
  28 .SH RETURN VALUE
  29 .BR getpt ()
  30 returns an open file descriptor upon successful completion.
  31 Otherwise, it
  32 returns \-1 and sets
  33 .I errno
  34 to indicate the error.
  35 .SH ERRORS
  36 .BR getpt ()
  37 can fail with various errors described in
  38 .BR open (2).
  39 .SH VERSIONS
  40 .BR getpt ()
  41 is provided in glibc since version 2.1.
  42 .SH ATTRIBUTES
  43 For an explanation of the terms used in this section, see
  44 .BR attributes (7).
  45 .TS
  46 allbox;
  47 lb lb lb
  48 l l l.
  49 Interface       Attribute       Value
  50 T{
  51 .BR getpt ()
  52 T}      Thread safety   MT-Safe
  53 .TE
  54 .SH CONFORMING TO
  55 .BR getpt ()
  56 is glibc-specific;
  57 use
  58 .BR posix_openpt (3)
  59 instead.
  60 .SH SEE ALSO
  61 .BR grantpt (3),
  62 .BR posix_openpt (3),
  63 .BR ptsname (3),
  64 .BR unlockpt (3),
  65 .BR ptmx (4),
  66 .BR pty (7)