posix_openpt - open a pseudoterminal device
int posix_openpt(int flags);
_XOPEN_SOURCE >= 600
The posix_openpt() function opens an unused pseudoterminal master device,
returning a file descriptor that can be used to refer to that device.
The flags argument is a bit mask that ORs together zero or
more of the following flags:
On success, posix_openpt() returns a file descriptor (a nonnegative
integer) which is the lowest numbered unused file descriptor. On failure, -1
is returned, and errno is set to indicate the error.
Glibc support for posix_openpt() has been provided since version 2.2.1.
For an explanation of the terms used in this section, see attributes(7).
- Open the device for both reading and writing. It is usual to specify this
- Do not make this device the controlling terminal for the process.
posix_openpt() is part of the UNIX 98 pseudoterminal
support (see pts(4)).
Some older UNIX implementations that support System V (aka UNIX 98)
pseudoterminals don't have this function, but it can be easily implemented by
opening the pseudoterminal multiplexor device:
return open("/dev/ptmx", flags);
Calling posix_openpt() creates a pathname for the
corresponding pseudoterminal slave device. The pathname of the slave device
can be obtained using ptsname(3). The slave device pathname exists
only as long as the master device is open.
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