Allegro 4.4.2 On Visual Studio 2013 Unhandled Exception - c++

Question

I´m starting to use allegro 4.4.2 on Visual Studio 2013. I installed both allegro 4.4.2 and 5.0.10 on VS and started testing some examples of allegro 4.4.2
This is my code:
#include <allegro.h>
#define ANCHO 640
#define ALTO 480
int soltado = 1;
int accion = 4;
BITMAP *buffer;
BITMAP *dibujo;
BITMAP *botones;
bool Sobre_boton(){
return (mouse_x >0 && mouse_x < 64 &&
mouse_y >0 && mouse_y < 64);
};
void cambiaccion(){};
void realizaccion(){};
void Boton_izquierdo(){
if (Sobre_boton()){
cambiaccion();
}
else{
realizaccion();
}
};
void Pinta_cursor(){
circle(buffer, mouse_x, mouse_y, 2, 0x000000);
putpixel(buffer, mouse_x, mouse_y, 0x000000);
};
void Pinta_botones(){
blit(botones, buffer, 0, 0, 0, 0, 64, 64);
};
int main()
{
allegro_init();
install_keyboard();
install_mouse();
set_color_depth(32);
set_gfx_mode(GFX_AUTODETECT_WINDOWED, ANCHO, ALTO, 0, 0);
buffer = create_bitmap(ANCHO, ALTO);
dibujo = create_bitmap(ANCHO, ALTO);
botones = load_bmp("bton.bmp", NULL);
clear_to_color(buffer, 0xFFFFFF);
clear_to_color(dibujo, 0xFFFFFF);
while (!key[KEY_ESC]){
blit(dibujo, buffer, 0, 0, 0, 0, ANCHO, ALTO);
Pinta_botones();
//pulsa boton izquierdo
if (mouse_b & 1){
Boton_izquierdo();
}
else{
soltado = 1;
}
Pinta_cursor();
blit(buffer, screen, 0, 0, 0, 0, ANCHO, ALTO);
}
destroy_bitmap(botones);
destroy_bitmap(dibujo);
destroy_bitmap(buffer);
return 0;
}
END_OF_MAIN();
When I run the project, VS starts lagging horribly, to the point I have to wait like 7 seconds to see my mouse cursor move. I have to terminate the process of VS in order to get my pc to work normally again. Here´s a screenshot of the exception:
Can anyone tell what I´m doing wrong?
Thank you

Answer 1

In this part botones = load_bmp("bton.bmp", NULL); you should add something after, like:
if( botones == NULL )
return 0;
To validate whether it was loaded properly or not, as load_bmp will return a NULL pointer if it fails to correctly load the file. When Pinta_botones is called, the function blit is called, whose functionality is to copy a rectangular area of the source bitmap to the destination bitmap.
The source bitmap, in this case botones appears to be a NULL pointer in the screenshot when blit is called, which will cause problems when trying to access a NULL reference.