Fix for being able to compile QtDMM on Gentoo Linux

[Strunzdesign]

Hi,

at first I want to thank you that you provide QtDMM for Qt5 on Github. I found your repository today and want to use it together with my Voltcraft VC870. But back to that device later...

1st issue) In order to build QtDMM, I had to modify the file src/src.pro:

Before:
lrelease.commands = $$[QT_INSTALL_BINS]/lrelease-qt5 ${QMAKE_FILE_IN} -qm translations/${QMAKE_FILE_BASE}.qm

After:
lrelease.commands = $$[QT_INSTALL_BINS]/lrelease ${QMAKE_FILE_IN} -qm translations/${QMAKE_FILE_BASE}.qm

On my system (Gentoo Linux, Qt-5.6.1) there is no file "lrelease-qt5". Here, it is just called "lrelease" without the suffix. If you also have the "lrelease" file on your disk, it would be better to refer to that instead.

2nd issue) For the INSTALL instructions file:
I have both "Qt 4.8.6" and Qt 5.6.1" installed on my system. If I just configure with a plain "qmake" call it will refer to Qt4 and break later during the make process. The solution was to invoke it using "QT_SELECT=qt5 qmake". Perhaps this is worth to be mentioned in your instructions file. Or better, maybe there is some kind of additional statement that Qt5 is a requirement, so that qmake automatically selects Qt5 instead of Qt4?

Regarding the VC870 multimeter: this device is currently not supported as it uses a 23 byte protocol that was not implemented for QtDMM yet. The specs for that are available and I already had a look into your sources and am sure that I can add the missing functionality easily. But before doing that, can you please clarify how your project relates to "http://www.mtoussaint.de/qtdmm.html" in terms of updates / merges? His repository seems active, but it still depends on Qt4. Is it better to add support for the VC870 there, and you merge it, or did both repositories diverted too much? What do you recommend?

Thanks, kind regards,
Florian

[tuxmaster]

To the first, it is the problem, that the translation tool, on every distribution it will have another name. So I don't have an idea for an general solution. For example on Fedora based it will called lrelease-qt5 for Qt5 and release-qt4. When some one has an idea, than patched are welcome.

To the second one:
There is the same problem as with the translation tool. On every distribution the tool has other name. :( qmake-qt4 and qmake-qt5 for Fedora based. Because the Qt stuff are very differ it can be hart to port it. But the part of reading the dmm are most the same, with the only difference, that I use the Qt functions to access the serial port. So I think, when you are firm in c++ you can easily port it back. And send an commit. Because I can't test it in missing of the device. My code was based on 0.9.0 of it.