Compiling a source file under Linux

[minas1]

So I have successfully installed irrlicht in Ubuntu and put the irrlicht folder in usr/ folder.

Now I am trying to compile a source file myself.

Here's my source code, which is pretty simple:

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#include <irrlicht.h>
 
using namespace irr;
 
using namespace core;
using namespace scene;
using namespace video;
using namespace io;
using namespace gui;
 
int main()
{
        IrrlichtDevice *device = createDevice(video::EDT_OPENGL, dimension2d<u32>(640, 480), 16, false, false, false, 0);
        
        device->drop();
        
        return 0;
}

And this is the makefile:

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main:   main.cpp
        g++ -L/usr/irrlicht-1.7.2/lib/Linux -I/usr/irrlicht-1.7.2/include -llibIrrlicht.a main.cpp -o test
        
clean:
        rm test
 

As you can see I have specified the include and lib directories to g++. However, when I type "make", I get this error message:

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g++ -L/usr/irrlicht-1.7.2/lib/Linux -I/usr/irrlicht-1.7.2/include -llibIrrlicht.a main.cpp -o test
/usr/bin/ld: cannot find -llibIrrlicht.a
collect2: ld returned 1 exit status
make: *** [main] Error 1
 

In the directory of my project there's only the source file (main.cpp) and the makefile. Why isn't it compiling?

[mongoose7]

I guess you don't know how to use '-l'. If I use '-lXXX', then the linker will look for the libraries libXXX.a and libXXX.so using the default search path extended by '-L' declarations. Maybe you should just bung <path to Irrlicht lib>/libIrrlicht.a straight on the command line?

[minas1]

OK, I changed the makefile.

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main:   main.cpp
        g++ -L/usr/irrlicht-1.7.2/lib/Linux/libIrrlicht.a -I/usr/irrlicht-1.7.2/include main.cpp -o test
        
clean:
        rm test

I still get an error:

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g++ -L/usr/irrlicht-1.7.2/lib/Linux/libIrrlicht.a -I/usr/irrlicht-1.7.2/include main.cpp -o test
/tmp/cc5HdsFY.o: In function `main':
main.cpp:(.text+0x58): undefined reference to `createDevice'
collect2: ld returned 1 exit status
make: *** [main] Error 1
 

[hybrid]

No, that's still not the correct way. Go back to version one and exchange -llibIrrlicht.a with -lIrrlicht
Also note that using a static lib means that you have to take care for file order. When using object files (.o) in your linker call, you have to put those before the libraries. Right now it's not important, though, as you only have .cpp files in your call. Just ask google for some help on makefiles. This is a very general thing, not in any way tied to Irrlicht.

[minas1]

Done. Same error...

g++ -L/usr/irrlicht-1.7.2/lib/Linux -I/usr/irrlicht-1.7.2/include -lIrrlicht main.cpp -o test
/tmp/ccdDL9Iw.o: In function `main':
main.cpp:(.text+0x58): undefined reference to `createDevice'
collect2: ld returned 1 exit status
make: *** [main] Error 1

[hybrid]

Looks like you use an incompatible or broken Irrlicht library. Did you compile it on your own?

[mongoose7]

Are you sure it's not because he has the object *after* the library? A library will only be searched if there are symbols to resolve at that point in the link - the linker won't go backwards and repeat a library search. Therefore, libraries should follow objects, as you yourself said. Also, the order of libraries is also imporatant as they are searched in order, though with one library it doesn't matter.

[hybrid]

Not sure about cpp files. Maybe the linker order is reproducing the original call order. In that case just move main.cpp one position ahead, just before the -lIrrlicht

[minas1]

I compiled the library again and put project folder inside irrlicht folder to test if it's working in there. I also changed my makefile to:

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test: main.o
        g++ -L../lib/Linux -lIrrlicht main.o -o test
 
main.o: main.cpp
        g++ -I../include main.cpp -c
 
clean:
        rm *.o *~ test

And I get this error again:

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g++ -L../lib/Linux -lIrrlicht main.o -o test
main.o: In function `main':
main.cpp:(.text+0x58): undefined reference to `createDevice'
collect2: ld returned 1 exit status
make: *** [test] Error 1
 

EDIT: If I put main.o before -lIrrlicht I get a full page of errors...

[CuteAlien]

Please start with the examples coming with Irrlicht. Do those compile and run?

[minas1]

Please start with the examples coming with Irrlicht. Do those compile and run?

Yes, they compiled and yes I can run them.

[minas1]

I found it! I copied the makefile from example_1 and changed the paths to correspond to my project and now it works. Looks like I was missing some includes and libraries..,

This is how it compiles:

g++ -I/usr/irrlicht-1.7.2/include -I/usr/X11R6/include -O3 -ffast-math main.cpp -o ./test -L/usr/irrlicht-1.7.2/lib/Linux -lIrrlicht -L/usr/X11R6/lib -lGL -lXxf86vm -lXext -lX11