2004-11-03 13:51:07 +00:00
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\" This page is in the public domain. - aeb
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.\"
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.TH GRANTPT 3 "2003-01-30" "PTY Control" "Linux Programmer's Manual"
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.SH NAME
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2004-12-17 11:28:00 +00:00
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grantpt \- grant access to the slave pseudo-terminal
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2004-11-03 13:51:07 +00:00
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.SH SYNOPSIS
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.nf
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.B #define _XOPEN_SOURCE
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.br
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.B #include <stdlib.h>
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.sp
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.BI "int grantpt(int " fd ");"
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.fi
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.SH DESCRIPTION
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The
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.BR grantpt ()
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function changes the mode and owner of the slave pseudo-terminal device
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(pty) corresponding to the master pty referred to by
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.IR fd .
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The user ID of the slave is set to the real UID of the calling process.
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The group ID is set to an unspecified value (e.g. tty).
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The mode of the slave is set to 0620 (crw\-\-w\-\-\-\-).
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.PP
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The behavior of
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.BR grantpt ()
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is unspecified if a signal handler is installed to catch SIGCHLD signals.
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.SH "RETURN VALUE"
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When successful,
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.BR grantpt ()
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returns 0. Otherwise, it returns \-1 and sets
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.I errno
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appropriately.
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.SH ERRORS
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.TP
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.B EACCES
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The corresponding slave pty could not be accessed.
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.TP
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.B EBADF
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The
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.I fd
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argument is not a valid open file descriptor.
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.TP
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.B EINVAL
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The
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.I fd
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argument is valid but not associated with a master pty.
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.SH "CONFORMING TO"
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POSIX 1003.1-2001
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.SH NOTES
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This is part of the Unix98 pty support, see
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.BR pts (4).
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2005-07-18 14:25:42 +00:00
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Many systems implement this function via a set-user-ID helper binary
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2004-11-03 13:51:07 +00:00
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called "pt_chown". With Linux devpts no such helper binary is required.
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.SH "SEE ALSO"
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.BR open (2),
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2004-12-17 12:46:00 +00:00
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.BR posix_openpt (3),
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2004-11-03 13:51:07 +00:00
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.BR ptsname (3),
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.BR unlockpt (3),
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2005-10-10 13:14:12 +00:00
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.BR pts (4),
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.BR pty (7)
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