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 pseu-
       doterminal device corresponding to the master  pseudoterminal  referred
       to by fd.  The user ID of the slave is set to the real UID of the call-
       ing 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 appropriately.

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 pseu-
	      doterminal.

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

ATTRIBUTES
       For  an	explanation  of	 the  terms  used   in	 this	section,   see
       attributes(7).

       +----------+---------------+----------------+
       |Interface | Attribute	  | Value	   |
       +----------+---------------+----------------+
       |grantpt() | Thread safety | MT-Safe locale |
       +----------+---------------+----------------+

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

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 4.10 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
       https://www.kernel.org/doc/man-pages/.



GNU				  2015-08-08			    GRANTPT(3)