grantpt - grant access to the slave pseudoterminal
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.
When successful, grantpt() returns 0. Otherwise, it returns -1 and sets
- The corresponding slave pseudoterminal could not be accessed.
- The fd argument is not a valid open file descriptor.
- The fd argument is valid but not associated with a master
grantpt() is provided in glibc since version 2.1.
For an explanation of the terms used in this section, see attributes(7).
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.
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