Calling QT c++ function from a c function: undefined reference

[viniltc]

Hi all
I am using two source code files - one with c code and the other with c++ code as well as using both c and c++ libraries.

The main function is c++ code. In the additional functions that i have written, I want to call c functions from some c++ functions and vice-versa.

I have defined the function (send_using_qtserial) to be called from a C file as this in my MainWindow.cpp

extern "C" size_t MainWindow::send_using_qtserial(uint8_t *data, size_t len)
{
    return serial->write((const char *)data, (qint64)len);
}

I have called that function in Protocol.c as follows:

extern size_t send_using_qtserial(uint8_t *data, size_t len);
size_t UART_Write_Out(const USART_MODULE_ID id, void * source, size_t nBytes)
{
    uint8_t *data= (uint8_t*)source;
    return send_using_qtserial(data, nBytes);
}

Unfortunately, I cannot seem to call a c++ function from a c function. I get the
the build error 'undefined reference to 'send_using_qtserial'' error for the c++ function in the c function I am trying to call it from.

Any suggestions?

[VRonin]

I want to call c functions from some c++

This is fine

and vice-versa

This is the problem. C doesn't know classes so it can't see methods inside classes.
You need to make send_using_qtserial a global static function, it can't be a method of MainWindow

[viniltc]

@VRonin Thanks a lot, I got your point