I am currently working on a Qt-based app that needs to communicate through the serial port. Apart from all the benefits that a normal lib with a serial port implementation will bring in this case, having a Qt-based serial port lib would make even more sense, as it should be as multiplatform as possible and use the signal/slot mechanism. Also it should have a DFSG-compatible license, so I can package it for Debian, of course :-)
So I have found two libs which seemed to have the above mentioned features: QExtSerialPort and QSerialPort.
QExtSerialPort seems to be the most recommended lib in the web. It features polled and signal-based functionality; it uses Qt's standard types inheriting QIODevice. But it does not states the license in any file within the source code. The original project page at SourceForge says it's in public domain. And the newer project page at Google code says it's under the new BSD license. I have asked in the mailing list for a clarification. So far nothing has changed (although in further threads the authors showed some willing to change this). And then I got to the point of finding a bug, but I don't want to spend time to track it down and make a patch without a clear license.
QSerialPort it's another lib with more or less the same features as QExtSerialPort. It's main LICENSE file says it's under the LGPL2, but licensecheck will say that the present files are LGPL3. Also, on reviewing the code, I found some minor stuff that could be improved. Well, I could contact the author and see if [s]he would receive the patches... but his site seems down. And I could not find a real-person's name in the code so far :-/
So I made a last attempt to try to get QExtSerialPort in a suitable license. If it doesn't suceed, I think I'll have to start writing one myself. The downside: I only use Linux, so there will be no multiplatform features unless someone else contributes it. Of course, if you have another option or any idea to share, I'll be happy to know it :-)
By the way, this should be my first post on Planet Debian in english, so hello planet!