Looking for addons in wrong directory

eversojk

I am currently following a tutorial for Allegro 5 and when trying to use al_draw_text, I get a seg fault. After using gdb, I found that it is looking in my downloads directory for the text addon. Any idea why this would be?

I am on Linux Mint 16, using g++ 4.8.1 and Allegro 5.0.11.

GDB output:

Program received signal SIGSEGV, Segmentation fault.
al_draw_ustr (font=font@entry=0x0, color=..., x=x@entry=50, y=50, flags=flags@entry=0, ustr=0x7fffffffdf80)
    at /home/me/Downloads/allegro/addons/font/text.c:93
93  /home/me/Downloads/allegro/addons/font/text.c: No such file or directory.

GDB backtrace:

#0  al_draw_ustr (font=font@entry=0x0, color=..., x=x@entry=50, y=50, flags=flags@entry=0, ustr=0x7fffffffdf80)
    at /home/me/Downloads/allegro/addons/font/text.c:93
#1  0x00007ffff76f5183 in al_draw_text (font=0x0, color=..., x=50, y=<optimized out>, flags=0, text=<optimized out>)
    at /home/me/Downloads/allegro/addons/font/text.c:106
#2  0x0000000000400c41 in main () at main.cpp:29

My tutorial file:

#SelectExpand
  1#include <allegro5/allegro.h>
  2#include <allegro5/allegro_font.h>
  3#include <allegro5/allegro_ttf.h>
  4#include <allegro5/allegro_native_dialog.h>
  5
  6int main(void) {
  7    ALLEGRO_DISPLAY *display = NULL;
  8
  9    if (!al_init()) {
 10        al_show_native_message_box(NULL, NULL, NULL,
 11            "failed to initialize allegro!", NULL, ALLEGRO_MESSAGEBOX_ERROR);
 12        return -1;
 13    }
 14
 15    display = al_create_display(640, 480);
 16
 17    if (!display) {
 18        al_show_native_message_box(NULL, NULL, NULL,
 19            "failed to initialize display!", NULL, ALLEGRO_MESSAGEBOX_ERROR);
 20        return -1;
 21    }
 22
 23    al_init_font_addon();
 24    al_init_ttf_addon();
 25
 26    ALLEGRO_FONT *font24 = al_load_font("/usr/share/fonts/truetype/ubuntu-font-family/Ubuntu-Mono-R.ttf", 24, 0);
 27
 28    al_clear_to_color(al_map_rgb(0, 0, 0));
 29    al_draw_text(font24, al_map_rgb(255, 0, 255), 50, 50, 0, "You like my font?");
 30    al_flip_display();
 31    al_rest(3.0);
 32    al_destroy_display(display);
 33
 34    return 0;
 35}

Makefile:

#SelectExpand
  1CXX=g++
  2CFLAGS=
  3LDFLAGS=-L/usr/lib -lallegro -lallegro_dialog -lallegro_font -lallegro_ttf
  4INCLUDE=-I. -I/usr/include/allegro5
  5
  6OBJS=main.cpp
  7OUT=main
  8
  9all: main
 10
 11main: $(OBJS); $(CXX) $(OBJS) -o $(OUT) $(INCLUDE) $(CFLAGS) $(LDFLAGS)
 12
 13debug: $(OBJS); $(CXX) -O0 -g $(OBJS) -o $(OUT) $(INCLUDE) $(CFLAGS) $(LDFLAGS)
 14
 15clean: ; rm -rf *.o main

pkrcel

Check if the font is actually loaded by verifing the retunr code of al_load_font

From what you posted it seems that GDB is looking for the source file in your downloads directory (which makes sense after all, I guess), but the SegFault seems due to invalid font pointer...which in turn may be caused by a failed load operation.

Someone will point out that you should always check return values...

eversojk

Thanks! I thought I had checked it but obviously I didn't, works fine now!

Thomas Fjellstrom

That no such file or directory message is just gdb looking for the source so it can show the source at the line it crashed at. It's not a fatal error or related to the crash at all.

Edgar Reynaldo

It is looking for the source code in the place it was compiled, which may have been on a different machine.

Thread #613920. Printed from Allegro.cc