NAME

     posix_openpt — open a pseudo-terminal device

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <stdlib.h>
     #include <fcntl.h>

     int
     posix_openpt(int oflag);

DESCRIPTION

     The posix_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

     pts(4), ptsname(3), tty(4)

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>