On Fri, 23 Sep 2022, Anthony Mallet wrote:
* POSIX does not mention the flag as supported in posix_openpt(3) (it
does not says it's not supported either :).
According to POSIX, anything other than O_RDWR or O_NOCTTY is "unspecified";
and, the FreeBSD man page explicitly states:
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.
So, O_NONBLOCK is, at least, _definitely_ non-portable. Best to use fcntl()
here and not depend on a Linux-specific behaviour.
-RVP
