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  corresponding  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 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
          pseudoterminal.

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

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   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/.

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