grantpt(S)

grantpt -- grant access to the slave pseudo-terminal device

Synopsis

   #include <sys/ptms.h>
   #include <stdlib.h>
   
   int grantpt(int fildes);

Description

The function grantpt changes the mode and ownership of the slave pseudo-terminal device associated with its master pseudo-terminal counter part. fildes is the file descriptor returned from a successful open of the master pseudo-terminal device. A setuid root program [see setuid(S)] is invoked to change the permissions. The user ID of the slave is set to the real owner of the calling process and the group ID is set to a reserved group. The permission mode of the slave pseudo-terminal is set to readable, writable by the owner and writable by the group.

Return values

Upon successful completion, the function grantpt returns 0; otherwise it returns -1.

Errors

Failure could occur if fildes is not an open file descriptor, if fildes is not associated with a master pseudo-terminal device, or if the corresponding slave device could not be accessed.

References

open(S), ptsname(S), pty(HW), setuid(S), unlockpt(S)