Library source in c and QT in c++ Will it work ??

johnnyde · 01-31-2005, 09:04 AM

hi
we are currently having a source code of a library in c. but according to the project we have to use QT interfac which is basically c++. so how do we integrate c in c++ or how to create a c library and use it in c++ programs??
thanks in advance
Johnny

nixcraft · 01-31-2005, 09:22 AM

I don't see any problems I had personally used this kind of stuff in past. Write code in QT/C++ call the functions from C++ code here is simple example:

my.c
… some code

my.h

void testme(){
}

qt.cpp
#include “my.h”

void myClass::test(){
testme();
}

main.cpp
main and other stuff

Run commands to build new project (QT/C++)
qmake –project
qmake
make

And you are done

Mara · 02-01-2005, 01:32 PM

There's no problem. You include header file for the library and can use its functions. Need only to make sure the program is linked with the library (so it usually means a need to modify program's Makefile).

nixcraft · 02-02-2005, 06:16 AM

Quote:

Originally posted by Mara
There's no problem. You include header file for the library and can use its functions. Need only to make sure the program is linked with the library (so it usually means a need to modify program's Makefile).

qmake -project
qmake

does this for you!

johnnyde · 02-02-2005, 10:23 AM

Ok. Thanks for the help guys. This is the spirit of open source . I did google and found some answers.
If you are including a C header file that isn't provided by the system, you may need to wrap the #include line in an extern "C" { /*...*/ } construct. This tells the C++ compiler that the functions declared in the header file are C functions.

Code:

  // This is C++ code   
 extern "C" { 
   // Get declaration for f(int i, char c, float x)  
  #include "my-C-code.h" 
 }
    int main() 
 { 
   f(7, 'x', 3.14);   // Note: nothing unusual in the call    ... 
 }

here is the link for the page.
http://www.inf.uni-konstanz.de/~kueh...c-and-cpp.html

http://gcc.gnu.org/ml/gcc-help/2001-11/msg00092.html - this page has a good explanation of technical complexities involved in mixing c and c++ and tells how to that too.

Thanks
I Salute the open source community

Johnnyde

Genjix · 02-03-2005, 01:54 PM

actually its good practice to include the wraps inside the header files themselves. you can also use gcc to compile the c files, g++ to compile the c++ files, then link with a linker (just use g++).