Problems when adding serialport module in Qt project

douglas · 13 Jun 2018, 06:56

Hi,
I need to use QSerialport in my Qt project. Following the official documentation, I added

QT       += serialport

to my .pro file. After doing this, the build always fails, giving the error: "Unknown module(s) in QT: serialport". I am using Qt Creator 4.1.0 based on Qt 5.6.1. What am I missing?
Thank you.

J.Hilk · wrote on 13 Jun 2018, 06:56

Hi @douglas

2 Questions:

did you rerun qmake after changing your .pro file?
for what OS are you trying to make the program? serialport is not available for all platforms

douglas · 13 Jun 2018, 07:43

Hi,
when I run qmake (Build menu -> Run qmake), I get the same error. I am trying to build an application for a device running Linux Yocto, and my host PC, in which Qt Creator is installed, has Uuntu 16.04 as O.S.
My .pro file first lines looks like the following:

QT       += core gui printsupport
QT       += serialport

Thank you!

aha_1980 · 13 Jun 2018, 07:47

@douglas

Which Qt version do you intend use?
How did you install Qt? If you installed with apt, you may add the serialport module explicitely.

douglas · 13 Jun 2018, 07:53

@aha_1980 I am using Qt 5.6.1. I installed Qt creator with apt. What do you mean with "add serialport explicitely"?
Thank you!

SGaist · wrote on 13 Jun 2018, 07:50

Hi,

What @aha_1980 asked was whether you also installed the Qt5 SerialPort package using apt.

KillerSmath · 13 Jun 2018, 07:57

@douglas
@aha_1980 told you need to install the packages individualy.

sudo apt-get install libqt5serialport5
sudo apt-get install libqt5serialport5-dev

douglas · 13 Jun 2018, 08:15

@KillerSmath I installed those packages via Software Center. Perhaps have I to uninstall them and re-install via apt-get?
Could it be the reason for the "unknown module" error?

SGaist · 13 Jun 2018, 08:13

Silly question: are you sure you are using Qt 5 and not Qt 4 for your project ?

douglas · S SGaist 13 Jun 2018, 08:07

@SGaist Yes, the Help menu from Qt Creator reports:

In fact, I read that serialport module was not included in Qt4, but it seems I am using Qt5, this is the reason why I can't understand that build error..

SGaist · 13 Jun 2018, 08:23

That's just the information about Qt Creator.

You have to check the Kit you are using to build your application and which version of Qt it is using.

KillerSmath · wrote on 13 Jun 2018, 08:15

@douglas
If nothing works, you can try to manage the packages from MaintenanceTool of QtCreator

1. <Qt Folder>/MaintenanceTool
1. Add or remove Components
1. Expand your Qt version
1. Expand Source Components
1. Select the Qt Source Package
1. Next, Install

douglas · 13 Jun 2018, 08:29

@SGaist how can I make sure of the Qt version I am using in my project?

KillerSmath · wrote on 13 Jun 2018, 08:28

This post is deleted!

J.Hilk · 13 Jun 2018, 08:45

@douglas
In QtCreator go to Tools -> Options -> build & run and check your kits

In sidebar under the "Projects tab" you can select one of your installed kits:

douglas · 13 Jun 2018, 08:48

@J.Hilk My environment is a bit different; I can't find informations about the version..

J.Hilk · 13 Jun 2018, 09:34

@douglas
from what one can see, it at least seems to be a version of Qt5, for more information press the "Manage kits" button

douglas · 13 Jun 2018, 09:38

@J.Hilk The Manage Kit button shows the settings reported below, in which I can't find any information regarding the Qt version in use:

If from terminal I write

$ qmake --version

I obtain the following:

qmake: could not exec '/usr/lib/x86_64-linux-gnu/qt4/bin/qmake': No such file or directory

Is it relevant the "qt4" shown in that prompt?
Thanks.

J.Hilk · 13 Jun 2018, 10:07

@douglas
well, there we have your problem

you have no QtLibary selected to your kit. Se if you can actually select a QtVersion from that dropdown menu. If you can't than you need to install an actual qt version.

I would recommend the online installer from the Webside.

douglas · 13 Jun 2018, 11:47

@J.Hilk Thanks, I added the version as shown below:

Now, since I should have Qt5, I added the serialport support in my .pro file, but the "unknow module" error still remains. I saw another thing that seems not so clear to me: I run Qt Creator from linux terminal, and when I open my project the terminal shows the following lines, marked in red, in which appears Qt4. Can this be related to the serialport module error?

thank you again.