mirror of https://github.com/mkerrisk/man-pages
70 lines
1.6 KiB
Groff
70 lines
1.6 KiB
Groff
.\" %%%LICENSE_START(PUBLIC_DOMAIN)
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.\" This page is in the public domain. - aeb
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.\" %%%LICENSE_END
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.\"
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.TH GRANTPT 3 2008-06-14 "GNU" "Linux Programmer's Manual"
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.SH NAME
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grantpt \- grant access to the slave pseudoterminal
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.SH SYNOPSIS
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.nf
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.BR "#define _XOPEN_SOURCE" " /* See feature_test_macros(7) */"
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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 pseudoterminal device
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corresponding to the master pseudoterminal 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., \fItty\fP).
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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
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.B SIGCHLD
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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.
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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 pseudoterminal 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 pseudoterminal.
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.SH VERSIONS
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.BR grantpt ()
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is provided in glibc since version 2.1.
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.SH CONFORMING TO
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POSIX.1-2001.
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.SH NOTES
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This is part of the UNIX 98 pseudoterminal support, see
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.BR pts (4).
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Many systems implement this function via a set-user-ID helper binary
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called "pt_chown".
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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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.BR posix_openpt (3),
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.BR ptsname (3),
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.BR unlockpt (3),
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.BR pts (4),
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.BR pty (7)
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