NAME
posix_openpt —
open a pseudo-terminal
device
LIBRARY
library “libc”
SYNOPSIS
#include <fcntl.h>
#include <stdlib.h>
int
posix_openpt(int
oflag);
DESCRIPTION
Theposix_openpt()
function allocates a new pseudo-terminal and establishes a connection with its
master device. A slave device shall be created in
/dev/pts. After the pseudo-terminal has been
allocated, the slave device should have the proper permissions before it can
be used (see grantpt(3)). The name of the slave device can be determined by
calling ptsname(3).
The file status flags and file access modes of the open file
description shall be set according to the value of
oflag. Values for oflag are
constructed by a bitwise-inclusive OR of flags from the following list,
defined in <fcntl.h>:
O_RDWR- Open for reading and writing.
O_NOCTTY- If set
posix_openpt() shall not cause the terminal device to become the controlling terminal for the process. O_CLOEXEC- Set the close-on-exec flag for the new file descriptor.
The
posix_openpt()
function shall fail when oflag contains other
values.
RETURN VALUES
Upon successful completion, the
posix_openpt() function shall allocate a new
pseudo-terminal device and return a non-negative integer representing a file
descriptor, which is connected to its master device. Otherwise, -1 shall be
returned and errno set to indicate the error.
ERRORS
The posix_openpt() function shall fail
if:
- [
ENFILE] - The system file table is full.
- [
EINVAL] - The value of oflag is not valid.
- [
EAGAIN] - Out of pseudo-terminal resources.
SEE ALSO
STANDARDS
The posix_openpt() function conforms to
IEEE Std 1003.1-2001 (“POSIX.1”). The
ability to use O_CLOEXEC is an extension to the
standard.
HISTORY
The posix_openpt() function appeared in
FreeBSD 5.0. In FreeBSD 8.0,
this function was changed to a system call.
NOTES
The flag O_NOCTTY is included for
compatibility; in FreeBSD, opening a terminal does
not cause it to become a process's controlling terminal.
AUTHORS
Ed Schouten <ed@FreeBSD.org>