How to use C code in qt?

[mlong]

If the C-based code is a standalone program, it might be possible to use QProcess to run it, and then capture the output and show it in a widget. Not sure if that's a viable option for you or not, though.

[zester]

shakthi

With some C you will need to use extern "C" and you might have to
convert some C types to Qt C++ . Smae goes with C++ std to Qt.

For a regular C string, just use the main constructor:

@char name[] = "Stack Overflow";
qDebug() << QString qname(name);
@
or

@std::string str("character/test/raw");
qDebug() << QString::fromStdString(str);
@
or

@std::string str("character/test/raw");
QString qstr(str.c_str());
qDebug() << qstr;@

Edit: please use @ tags around code sections; Andre

[raja26]

I have used C code withing Qt without any problem, to be exact I have used the languages C (with OpenSSL library), C++, Qt, QML, Javascript, HTML in a single application without too much effort. I don't think that you have to do something to mix C, C++ and Qt.

OK, now for example: the following code will use C and Qt.

@
#include <QApplication>
#include <QLabel>

//C Header files
#include <stdlib.h>

int main(int argc, char* argv[])
{
int 1;
char a[] = "64";
i = atoi(a);//C function to convert char to integer
QApplication app(argc, argv);
QLabel label(QString("Actual char: " + a + "Integer :" + QString::fromNumber(i) )); //char to QString
return app.exec();
}
@

All you h

[vivekyuvan]

Hi@DenisKormalev I need to interface C driver code to QT GUI, Can you show me a snippet to achieve the linking process from C source code to QT GUI

Ex 
unsigned int a[100]={ 25,  17 , 10,  6,  -5 , -6, -8 , 10, ......... };

I am required to send this array data to QT GUI through Slots, from C source file to QT Slots is that possible?

If possible please someone shows the code snippet in QT that will help me a lot

[jsulm]

@vivekyuvan said in How to use C code in qt?:

I am required to send this array data to QT GUI through Slots, from C source file to QT Slots is that possible?

No it's not as your C driver code isn't based on Qt, right? You will need to call the interface functions of your C driver in your app.

[vivekyuvan]

Hi@jsulm
I like to implement frontend alone in qt and backend is in C. The backend code was written in C its best to keep the code in C because its a driver code. so now my concern is can I communicate my driver code with frontend QT GUI?

// You will need to call the interface functions of your C driver in your app.//

some me some snipet to interface C code to qt with QDBUS IPC protocol

[jsulm]

@vivekyuvan You can use C code in a C++ project. I don't really understand what the problem is. Either add your C code directly to your project or add it as a shared library.
I can't give you any snippet of code to use this C code as I have no idea how it looks like. Take a look at its interface/API, read its documentation and find out how to use it. I can't/will not do it for you.

[vivekyuvan]

Hi@jsulm Ill explain in detail, first of all, I cant add my C driver code as the shared library because I am Implement the lightweight GUI application. hope you can understand lightweight GUI application.

A lot of driver code participate in my project like UART Driver and I2C Driver and SPI Driver, all driver code was written in C code.

So I can't wrap my driver code into QT Source code as well as its difficult to add all driver code as the shared lib in QT Source code

Because I am Implementing lightweight GUI application. My frontend QT code is just a window to monitor all parameters

So I am forced to create my driver code as like as demon process in the background. Then I catch the required data in QT QProcess class in the frontend code Is that possible?

[jsulm]

@vivekyuvan How is your "driver code" communicating with the outside world? If you start it as a deamon you need a way to communicate with it. So, how does your driver communicate? Does it have to run as a daemon? I suggested two solutions: one was shared library (I still don't understand why you think it is not possible), or add the C code to your Qt app. Can't you simply add C code to your Qt app?

[aha_1980]

@vivekyuvan

I cant add my C driver code as the shared library because I am Implement the lightweight GUI application

Both options are not mutally exclusive.

You really only have three options:

1. Add your C code directly in the Qt project (i.e. link it statically)
2. Add your C code as a shared library (i.e. link it dynamically)
3. Let your C code run as a standalone program (a daemon) and communicate with it by some interprocess communication method.

Note that for option 3 the daemon must be started by someone, in order to communicate with your GUI program.

Regards