Hello,

I´m new to c programming and in the book i´m following I am to write a game which requires Allegro.

I'm sitting on a windows 7 box and use mingw to compile my programs. I installed allegro "allegro-5.0.8-mingw-4.6.2" and mingw "mingw-get-inst-20120426.exe" and to verify that it´s working I found this code:
#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;
}

I've been failing so many times trying to compile this code. this is what I write at the "MinGW Shell":
/e/cbin/proj/allegro
$ gcc -I/c/MinGW/include/allegro5 tst.c -o tst.exe
undefined reference to `al_install_system'
undefined reference to `al_create_display'
undefined reference to `al_map_rgb'
undefined reference to `al_clear_to_color'
undefined reference to `al_flip_display'
undefined reference to `al_rest'
undefined reference to `al_destroy_display'

/e/cbin/proj/allegro
$ gcc -l/c/MinGW/include/allegro5 tst.c -o tst.exe
c:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../../mingw32/bin/ld.exe: cannot find -lc:/MinGW/include/allegro5

I´ve tried a lot of other combinations but I can´t compile this one? Any ideas?

Thanks for the reply!

Tried (in the "/e/cbin/proj/allegro" dir):
$ gcc -I/c/MinGW/include/allegro5 -L/c/MinGW/lib -lallegro tst.c -o tst.exe
c:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../../mingw32/bin/ld.exe: cannot find -lallegro
collect2: ld returned 1 exit status

Also this:
$ gcc -I/c/MinGW/include/allegro5 -L/c/MinGW/lib -lliballegro-5.0.8-mt tst.c -o tst.exe
c:/mingw/bin/../lib/gcc/mingw32/4.6.2/../../../../mingw32/bin/ld.exe: cannot find -lliballegro-5.0.8-mt
collect2: ld returned 1 exit status

Could I have missed some env variables?
User path says:
C:\MinGW\bin;C:\MinGW\msys\1.0\bin

This is what I have in the c:\mingw\lib

$ ls liballegro*
liballegro-5.0.8-md-debug.a
liballegro-5.0.8-md.a
liballegro-5.0.8-monolith-md-debug.a
liballegro-5.0.8-monolith-md.a
liballegro-5.0.8-monolith-mt-debug.a
liballegro-5.0.8-monolith-mt.a
liballegro-5.0.8-monolith-static-md-debug.a
liballegro-5.0.8-monolith-static-md.a
liballegro-5.0.8-monolith-static-mt-debug.a
liballegro-5.0.8-monolith-static-mt.a
liballegro-5.0.8-mt-debug.a
liballegro-5.0.8-mt.a
liballegro-5.0.8-static-md-debug.a
liballegro-5.0.8-static-md.a
liballegro-5.0.8-static-mt-debug.a
liballegro-5.0.8-static-mt.a
liballegro_acodec-5.0.8-md-debug.a
liballegro_acodec-5.0.8-md.a
liballegro_acodec-5.0.8-mt-debug.a
liballegro_acodec-5.0.8-mt.a
liballegro_acodec-5.0.8-static-md-debug.a
liballegro_acodec-5.0.8-static-md.a
liballegro_acodec-5.0.8-static-mt-debug.a
liballegro_acodec-5.0.8-static-mt.a
liballegro_audio-5.0.8-md-debug.a
liballegro_audio-5.0.8-md.a
liballegro_audio-5.0.8-mt-debug.a
liballegro_audio-5.0.8-mt.a
liballegro_audio-5.0.8-static-md-debug.a
liballegro_audio-5.0.8-static-md.a
liballegro_audio-5.0.8-static-mt-debug.a
liballegro_audio-5.0.8-static-mt.a
liballegro_color-5.0.8-md-debug.a
liballegro_color-5.0.8-md.a
liballegro_color-5.0.8-mt-debug.a
liballegro_color-5.0.8-mt.a
liballegro_color-5.0.8-static-md-debug.a
liballegro_color-5.0.8-static-md.a
liballegro_color-5.0.8-static-mt-debug.a
liballegro_color-5.0.8-static-mt.a
liballegro_dialog-5.0.8-md-debug.a
liballegro_dialog-5.0.8-md.a
liballegro_dialog-5.0.8-mt-debug.a
liballegro_dialog-5.0.8-mt.a
liballegro_dialog-5.0.8-static-md-debug.a
liballegro_dialog-5.0.8-static-md.a
liballegro_dialog-5.0.8-static-mt-debug.a
liballegro_dialog-5.0.8-static-mt.a
liballegro_font-5.0.8-md-debug.a
liballegro_font-5.0.8-md.a
liballegro_font-5.0.8-mt-debug.a
liballegro_font-5.0.8-mt.a
liballegro_font-5.0.8-static-md-debug.a
liballegro_font-5.0.8-static-md.a
liballegro_font-5.0.8-static-mt-debug.a
liballegro_font-5.0.8-static-mt.a
liballegro_image-5.0.8-md-debug.a
liballegro_image-5.0.8-md.a
liballegro_image-5.0.8-mt-debug.a
liballegro_image-5.0.8-mt.a
liballegro_image-5.0.8-static-md-debug.a
liballegro_image-5.0.8-static-md.a
liballegro_image-5.0.8-static-mt-debug.a
liballegro_image-5.0.8-static-mt.a
liballegro_memfile-5.0.8-md-debug.a
liballegro_memfile-5.0.8-md.a
liballegro_memfile-5.0.8-mt-debug.a
liballegro_memfile-5.0.8-mt.a
liballegro_memfile-5.0.8-static-md-debug.a
liballegro_memfile-5.0.8-static-md.a
liballegro_memfile-5.0.8-static-mt-debug.a
liballegro_memfile-5.0.8-static-mt.a
liballegro_physfs-5.0.8-md-debug.a
liballegro_physfs-5.0.8-md.a
liballegro_physfs-5.0.8-mt-debug.a
liballegro_physfs-5.0.8-mt.a
liballegro_physfs-5.0.8-static-md-debug.a
liballegro_physfs-5.0.8-static-md.a
liballegro_physfs-5.0.8-static-mt-debug.a
liballegro_physfs-5.0.8-static-mt.a
liballegro_primitives-5.0.8-md-debug.a
liballegro_primitives-5.0.8-md.a
liballegro_primitives-5.0.8-mt-debug.a
liballegro_primitives-5.0.8-mt.a
liballegro_primitives-5.0.8-static-md-debug.a
liballegro_primitives-5.0.8-static-md.a
liballegro_primitives-5.0.8-static-mt-debug.a
liballegro_primitives-5.0.8-static-mt.a
liballegro_ttf-5.0.8-md-debug.a
liballegro_ttf-5.0.8-md.a
liballegro_ttf-5.0.8-mt-debug.a
liballegro_ttf-5.0.8-mt.a
liballegro_ttf-5.0.8-static-md-debug.a
liballegro_ttf-5.0.8-static-md.a
liballegro_ttf-5.0.8-static-mt-debug.a
liballegro_ttf-5.0.8-static-mt.a

Am I typing the gcc command wrong? The source file is located in e:\cbin\proj\allegro and is called "tst.c". When I run the command I am in that directory:

Is there something wrong with this line?
$ gcc -I/c/MinGW/include/allegro5 -L/c/MinGW/lib -lallegro-5.0.8-monolith-mt tst.c -o tst.exe

It shows these errors:
undefined reference to `al_install_system'
undefined reference to `al_create_display'
undefined reference to `al_map_rgb'
undefined reference to `al_clear_to_color'
undefined reference to `al_flip_display'
undefined reference to `al_rest'
undefined reference to `al_destroy_display'

Awesome! that did compile:
$ gcc tst.c -lallegro-5.0.8-monolith-mt -o tst.exe

$ tst.exe

When I ran the program I got an error popup saying:
"The program can´t start because.... blabla can´t find allegro-5.0.8-monolith-mt.dll"

I copied that dll from the location of the unzipped allegro bin folder to C:\MinGW\bin folder and ran the program again and I got no errors. So I´m guessing everything works fine.

There were a lot of DLL's in the unzip folder. Should I copy all of those to the C:\minGW\bin folder?

Yeah that sounds smarter.

Thanks for all the help. Now I can finally get to the actual coding.

Cheers

I have a similar problem, but I am using C++ as my main language using allegro 5.0.7

Before I tell you the details, I will give you specifics

//////
Specifics:

Operating System: Mac OSX 10.6 Snow Leopard (Intel)
Programming environment: Terminal (UNIX)
I did not copy and paste the library files onto the directory containing the program.
//////

I have attempted to do the following steps from the previous post, but I get a series of undefined errors:

before using library calling

g++ -Wall -Wextra -o allegro_start allegro_start.cpp
Undefined symbols:
"_main", referenced from:
start in crt1.10.6.o
(maybe you meant: __al_mangled_main)
"_al_rest", referenced from:
__al_mangled_main in ccExARhf.o
"_al_install_system", referenced from:
__al_mangled_main in ccExARhf.o
"_al_create_display", referenced from:
__al_mangled_main in ccExARhf.o
"_al_flip_display", referenced from:
__al_mangled_main in ccExARhf.o
"_al_destroy_display", referenced from:
__al_mangled_main in ccExARhf.o
"_al_map_rgb", referenced from:
__al_mangled_main in ccExARhf.o
"_al_clear_to_color", referenced from:
__al_mangled_main in ccExARhf.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

I even tried for getting the main file to work

g++ allegro_start.cpp -Wall -Wextra -lallegro-5.0.7-main -o allegro_start
ld: library not found for -lallegro-5.0.7-main
collect2: ld returned 1 exit status

It's my first time using Allegro game engine too

Thank you, those were the two commands needed to correctly compile the program , and I wonder what is the significance of -lallegro -lallegro_main?

i.e g++ allegro_start.cpp -Wall -Wextra -lallegro -lallegro_main -o allegro_start

I might add that the stuff in libraries could be in source files in your project, but obviously linking all of Allegro each time you started a new project would be a pain. Libraries are kind of a systemwide collection of useful routines that are (hopefully) debugged, so you don't need the source for those functions in your project.

For instance, I find the Mersenne random number generator to be quite useful, so I made a library for it and stuck it in with the other local (to this computer) libraries such as Allegro, and put a mersenne.h in the local includes. It does break projects you give to other people though, since they most likely don't have such a library, so you have to include the source and header again.