tcp.7: Update info on tcp_syn_retries default value

[thirdparty/man-pages.git] / man3 / getpt.3

.\" This man page was written by Jeremy Phelps <jphelps@notreached.net>.
.\"
.\" %%%LICENSE_START(FREELY_REDISTRIBUTABLE)
.\" Redistribute and modify at will.
.\" %%%LICENSE_END
.\"
.TH GETPT 3 2020-02-09 "GNU" "Linux Programmer's Manual"
.SH NAME
getpt \- open the pseudoterminal master (PTM)
.SH SYNOPSIS
.nf
.BR "#define _GNU_SOURCE" "             /* See feature_test_macros(7) */"
.B #include <stdlib.h>
.PP
.B "int getpt(void);"
.fi
.SH DESCRIPTION
.BR getpt ()
opens a pseudoterminal master and returns its file descriptor.
It is equivalent to
.PP
.in +4n
.EX
open("/dev/ptmx", O_RDWR);
.EE
.in
.PP
on Linux systems, though the pseudoterminal master is located
elsewhere on some systems that use GNU Libc.
.SH RETURN VALUE
.BR getpt ()
returns an open file descriptor upon successful completion.
Otherwise, it
returns \-1 and sets
.I errno
to indicate the error.
.SH ERRORS
.BR getpt ()
can fail with various errors described in
.BR open (2).
.SH VERSIONS
.BR getpt ()
is provided in glibc since version 2.1.
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lb lb lb
l l l.
Interface	Attribute	Value
T{
.BR getpt ()
T}	Thread safety	MT-Safe
.TE
.SH CONFORMING TO
.BR getpt ()
is glibc-specific;
use
.BR posix_openpt (3)
instead.
.SH SEE ALSO
.BR grantpt (3),
.BR posix_openpt (3),
.BR ptsname (3),
.BR unlockpt (3),
.BR ptmx (4),
.BR pty (7)