GRANTPT(3)                          Linux Programmer's Manual                          GRANTPT(3)



NAME
       grantpt - grant access to the slave pseudoterminal

SYNOPSIS
       #define _XOPEN_SOURCE       /* See feature_test_macros(7) */
       #include <stdlib.h>

       int grantpt(int fd);

DESCRIPTION
       The  grantpt() function changes the mode and owner of the slave pseudoterminal device cor‐
       responding to the master pseudoterminal referred to by fd.  The user ID of  the  slave  is
       set  to  the real UID of the calling process.  The group ID is set to an unspecified value
       (e.g., tty).  The mode of the slave is set to 0620 (crw--w----).

       The behavior of grantpt() is unspecified if a signal handler is installed to catch SIGCHLD
       signals.

RETURN VALUE
       When  successful,  grantpt() returns 0.  Otherwise, it returns -1 and sets errno appropri‐
       ately.

ERRORS
       EACCES The corresponding slave pseudoterminal could not be accessed.

       EBADF  The fd argument is not a valid open file descriptor.

       EINVAL The fd argument is valid but not associated with a master pseudoterminal.

VERSIONS
       grantpt() is provided in glibc since version 2.1.

CONFORMING TO
       POSIX.1-2001.

NOTES
       This is part of the UNIX 98 pseudoterminal support, see pts(4).   Many  systems  implement
       this  function  via  a  set-user-ID helper binary called "pt_chown".  With Linux devpts no
       such helper binary is required.

SEE ALSO
       open(2), posix_openpt(3), ptsname(3), unlockpt(3), pts(4), pty(7)

COLOPHON
       This page is part of release 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



GNU                                         2008-06-14                                 GRANTPT(3)