grantpt - grant access to the slave pseudo-terminal device
#include <stdlib.h> int grantpt(int fildes);
The grantpt() function changes the mode and ownership of the slave pseudo-terminal device associated with its master pseudo-terminal counter part. The fildes argument is a file descriptor that refers to a master pseudo-terminal device. The user ID of the slave is set to the real UID of the calling process and the group ID is set to an unspecified group ID. The permission mode of the slave pseudo-terminal is set to readable and writable by the owner, and writable by the group.
The behaviour of the grantpt() function is unspecified if the application has installed a signal handler to catch SIGCHLD signals
Upon successful completion, grantpt() returns 0. Otherwise, it returns -1 and sets errno to indicate the error.
The grantpt() function may fail if:
- The fildes argument is not a valid open file descriptor.
- The fildes argument is not associated with a master pseudo-terminal device.
- The corresponding slave pseudo-terminal device could not be accessed.
open(), ptsname(), unlockpt(), <stdlib.h>.