[yanom]

I tried compiling this example program using the allegro graphics library:

#include <allegro.h>

const int scrx = 640;
const int scry = 480;

int main(int argc, char* argv[]) {
  if (allegro_init()) {
    allegro_message("Cannot initalize Allegro.\n");
    return 1;
  }

  //Set the window title when in a GUI environment
  set_window_title("Hello World");

  if (install_keyboard()) {
    allegro_message("Cannot initalize keyboard input.\n");
    return 1;
  }

  //set graphics mode, trying all acceptable depths
  set_color_depth(32);
  if (set_gfx_mode(GFX_AUTODETECT, scrx, scry, 0, 0)) {
    set_color_depth(24);
    if (set_gfx_mode(GFX_AUTODETECT, scrx, scry, 0, 0)) {
      set_color_depth(16);
      if (set_gfx_mode(GFX_AUTODETECT, scrx, scry, 0, 0)) {
        set_color_depth(15);
        if (set_gfx_mode(GFX_AUTODETECT, scrx, scry, 0, 0)) {
          allegro_message("Video Error: %s.\n", allegro_error);
          return 1;
        }
      }
    }
  }

  //set text background color to bright blue
  text_mode(makecol(0, 0, 255));

  //prints yellow "Hello World!!!" in middle of screen
  textout_centre(screen, font, "Hello World!!!", scrx/2,
                 scry/2, makecol(255, 255, 0));

  //Wait for a key to be pressed
  while (!keypressed()) {}

  return 0;
  //Allegro will automatically deinitalize itself on exit
}
END_OF_MAIN()

but it throws some crazy errors, like "undefined reference to <<something or other>>". The error log is attached. I used this makefile (command "make all"):

CC=gcc
NAME=main
FILES=main.c
LF=-lalleg

all: default

default: build

build:
    $(CC) -o $(NAME) $(FILES) $(LF)

clean:
    rm -rf *.o
    rm -rf $(NAME)

destroy:
    rm -rf ./*

Attached File(s)

•  allegerr.txt (31.75K)
  Number of downloads: 262

[Oler1s]

You aren't linking to the math and Xlib library. You could figure this out yourself, or you could use allegro-config or pkg-config to do the job. For example, gcc myfile.c -o myprogram `allegro-config --libs`.

Of course, you want to make use of your makefile, so running allegro-config --libs to get the information, and then using that information in your makefile is a smart idea.

[Seta00]

Oler1s, on 25 September 2010 - 07:12 PM, said:

You aren't linking to the math and Xlib library. You could figure this out yourself, or you could use allegro-config or pkg-config to do the job. For example, gcc myfile.c -o myprogram `allegro-config --libs`.

Of course, you want to make use of your makefile, so running allegro-config --libs to get the information, and then using that information in your makefile is a smart idea.

IIRC you can add the command itself to the makefile.

[yanom]

OK, thanks