Compiling C++ code with allegro 5 and g++ - c++

Question

What flags do I need to add to g++ in order to compile code using allegro 5? I tried
g++ allegro5test.cpp -o allegro5test `allegro-config --libs`
but that is not working. I'm using ubuntu 11.04. I installed allegro 5 using the instructions at http://wiki.allegro.cc/index.php?title=Install_Allegro5_From_SVN/Linux/Debian
I tried:
g++ allegro5test.cpp -o allegro5test `allegro-config --cflags --libs`
And it also gives a bunch of undefined errors, like: undefined reference to `al_install_system'
allegro-config --cflags --libs outputs:
-I/usr/local/include
-L/usr/local/lib -lalleg

Answer 1

So you successfully installed allegro5 on your system from the SVN. One thing you should know is that this build doesn't come with allegro-config. If you have it on your system it means you have previously installed allegro4.
allegro5 brings many changes, including different initialization procedures, library and function names.
Here's a hello world application for new version:
#include <stdio.h>
#include <allegro5/allegro.h>
int main(int argc, char **argv)
{
ALLEGRO_DISPLAY *display = NULL;
if(!al_init()) {
fprintf(stderr, "failed to initialize allegro!\n");
return -1;
}
display = al_create_display(640, 480);
if(!display) {
fprintf(stderr, "failed to create display!\n");
return -1;
}
al_clear_to_color(al_map_rgb(0,0,0));
al_flip_display();
al_rest(10.0);
al_destroy_display(display);
return 0;
}
Notice how the command to compile this application refers to another include directory and library names, which are different from the previous version of allegro:
g++ hello.cpp -o hello -I/usr/include/allegro5 -L/usr/lib -lallegro

Answer 2

Allegro 5 uses pkg-config.
pkg-config --libs allegro-5.0 allegro_image-5.0
And so on for each library you are using.