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POSIX_OPENPT(2) | System Calls Manual | POSIX_OPENPT(2) |
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¶
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.
posix_openpt
() function shall fail when
oflag contains other values.
RETURN VALUES¶
Upon successful completion, theposix_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¶
Theposix_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¶
Theposix_openpt
() function conforms to
IEEE Std 1003.1-2001
(“POSIX.1”). The ability to use
O_CLOEXEC
is an extension to the standard.
HISTORY¶
Theposix_openpt
() function appeared in
FreeBSD 5.0. In FreeBSD 8.0,
this function was changed to a system call.
NOTES¶
The flagO_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⟩March 21, 2013 | Debian |