int posix_openpt(int flags);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
posix_openpt(): _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
The flags argument is a bit mask that ORs together zero or more of the
O_RDWR Open the device for both reading and writing. It is usual to
specify this flag.
Do not make this device the controlling terminal for the
On success, posix_openpt() returns a nonnegative file descriptor which
is the lowest numbered unused 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.
posix_openpt() is part of the UNIX 98 pseudoterminal support (see
pts(4)). This function is specified in POSIX.1-2001.
The posix_openpt() function is a recent invention in POSIX. Some UNIX
implementations that support System V (aka UNIX 98) pseudoterminals
don't have this function, but it is easy to implement:
return open("/dev/ptmx", flags);
Calling posix_openpt() creates a pathname for the corresponding pseu-
doterminal slave device. The pathname of the slave device can be
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