Compiling C/GTK within Eclipse

Question

I'm fiddling around with the C/C++ version of Eclipse to build a simple GTK app. However, I can't seem to be able to compile a GTK sample from within Eclipse. I can compile a simple Hello World style test app, so I know the tool chain itself is working. However, the moment I start adding GTK into the mix the compiler comes up with errors. The funny thing is that I can compile the examples outside the Eclipse environment just fine. E.g., I'm using the examples on this page and following the instructions given there let me build a working binary.

I think the first problem is that the main GTK include file is referenced differently when I try to compile within Eclipse. The non-Eclipse version I can compile with (as in the example):

#include <gtk/gtk.h>

However, within Eclipse this doesn't work. I need to change it to:

#include <gtk-2.0/gtk/gtk.h>

The include file can then be found but the compilation process then starts to throw errors about the GtkWidget type. E.g.:

#include <gtk-2.0/gtk/gtk.h>

int main( int argc, char *argv[] )
{
    GtkWidget *window;

    gtk_init (&argc, &argv);

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
    gtk_widget_show  (window);

    gtk_main ();

    return 0;
}

Results in these errors:

make all 
Building file: ../src/main.c
Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/main.d" -MT"src/main.d" -o"src/main.o" "../src/main.c"
../src/main.c: In function ‘main’:
../src/main.c:7: error: ‘GtkWidget’ undeclared (first use in this function)
../src/main.c:7: error: (Each undeclared identifier is reported only once
../src/main.c:7: error: for each function it appears in.)
../src/main.c:7: error: ‘window’ undeclared (first use in this function)
../src/main.c:9: warning: implicit declaration of function ‘gtk_init’
../src/main.c:11: warning: implicit declaration of function ‘gtk_window_new’
../src/main.c:11: error: ‘GTK_WINDOW_TOPLEVEL’ undeclared (first use in this function)
../src/main.c:12: warning: implicit declaration of function ‘gtk_widget_show’
../src/main.c:14: warning: implicit declaration of function ‘gtk_main’
make: *** [src/main.o] Error 1

Not sure how to go about this. Any assistance would be very much appreciated.

Answer 1

Try adding the gtk directory to the build path:

Go into project Properties -> C/C++ build -> Settings -> Tool settings -> Directories and add it under Include paths.

Answer 2

Right click the Eclipse project and select properties. From the Configuration drop down, select [ All configurations ]. Then on the Tool Settings tab select GCC C Compiler (default) and add the following to the end Command line pattern (Expert settings) box:

`pkg-config --cflags --libs gtk+-2.0`

Do the same thing for the GCC C Linker option.

If you don't want to start your include paths with gtk-2.0 than also add the include directory (/usr/include/gtk-2.0) like aardvark suggested.