Termios speed setting problem

[hpax]

Since glibc 2.42 Linux glibc supports arbitrary baud rates directly; several other Unices have done that for a long time.

The code in serial.c has several serious problems, however:

1. Manipulating c_cflag directly is not the correct way to set baud rates for any system; that was the method used with the termio (not termios) interface, but termios has always required the use of cfset[io]speed().
2. If the Bxxx constants match the respective xxx values then it should be safe to use them as integers directly. For Linux specifically, you can simply test for B300 == 300.
3. Don't use TIOCGSERIAL for these newer systems; using TIOCGSERIAL breaks other applications.
4. Glibc 2.42 added cfset[io]baud() which is explicitly defined as numeric, if you don't trust relying on testing the Bxxx constants; however, that will not yet work on other Unices.

The stty code in GNU coreutils has been augmented with autodetection of supported speeds to a specific platform. You might find that interesting as an example.

[hpax]

See also: sigrokproject/libserialport#24

[hpax]

Here is a compile-tested-only patch for baud rate setting which should work on Linux with and without glibc 2.42+ as well as any other POSIX system with sane termios constants.

If broken, you get to keep both pieces ;)

baud-untested.patch.txt

[hpax]

I got inspired (I use gtkterm myself heavily) and so I wrote up a bunch of code for this...

#82

[wvdakker]

There are some major changes in the last code. Can you try if this solves your problem?

[hpax]

#82 fixes it, obviously :)