It seems GCC likes my code better than VS 2010

Basically, my code is just meant to load a BMP file, just to test SDL in Visual Studio. It works in Code::Blocks with MingW, and it worked in VS up until I added

Code:

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Uint32 colorkey = SDL_MapRGB(img->format, 0xFF, 0, 0xFF); //declare the key
SDL_SetColorKey(img, SDL_SRCCOLORKEY, colorkey); // set the key

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VS is pointing towards the key's declaration line, and saying "Unhandled exception at 0x00d9158a in SDL_Tutorial.exe: 0xC0000005: Access violation reading location 0x00000004." My entire program:

Code:

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#include <SDL.h>


int main( int argc, char* args[] )
{
        //Start SDL
    SDL_Init( SDL_INIT_EVERYTHING );
        //vars
        SDL_Surface *img;
        SDL_Surface *buffer;
        SDL_Rect crop;
        SDL_Rect loc;
        crop.x = 0;
        crop.y = 0;
        crop.w = 32;
        crop.h = 32;
        loc.x = 280;
        loc.y = 280;

       

 
   
        //load image onto screen
        img = SDL_LoadBMP("snakey.bmp");
        Uint32 colorkey = SDL_MapRGB(img->format, 0xFF, 0, 0xFF);

        SDL_SetColorKey(img, SDL_SRCCOLORKEY, colorkey); //make magneta invisible
        buffer = SDL_SetVideoMode( 640, 480, 32, SDL_SWSURFACE );
        SDL_BlitSurface(img, &crop, buffer, &loc);
        SDL_Flip(buffer);
        SDL_Delay(2000);
        //Quit SDL
        SDL_FreeSurface(buffer);
        SDL_FreeSurface(img);
    SDL_Quit();
   
    return 0;   
}

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Perhaps SDL_LoadBMP simply fails? Check return values.

Well, I edited it a little, to this:

Code:

---

#include <SDL.h>


int main( int argc, char* args[] )
{
        //Start SDL
    SDL_Init( SDL_INIT_EVERYTHING );
        //vars
        SDL_Surface *img;
        SDL_Surface *buffer;
        SDL_Rect crop;
        SDL_Rect loc;
        crop.x = 0;
        crop.y = 0;
        crop.w = 32;
        crop.h = 32;
        loc.x = 280;
        loc.y = 280;

       

 
   
        //load image onto screen
        img = SDL_LoadBMP("snakey.bmp");
        Uint32 colorkey = SDL_MapRGB(img->format, 0xFF, 0, 0xFF);

        SDL_SetColorKey(img, SDL_SRCCOLORKEY, colorkey); //make magneta invisible
        buffer = SDL_SetVideoMode( 640, 480, 32, SDL_SWSURFACE );
        SDL_BlitSurface(img, &crop, buffer, &loc);
        SDL_Flip(buffer);
        SDL_Delay(2000);
        //Quit SDL
        SDL_FreeSurface(buffer);
        SDL_FreeSurface(img);
    SDL_Quit();
   
    return 0;   
}

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but this only runs if I run the executable directly. Is that normal?

By checking return values I meant something like this:

Code:

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img = SDL_LoadBMP("snakey.bmp");
if (!img) {
    //output error message and quit
}

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It looks from the exception that your program is dereferencing a NULL pointer (or rather an offset of 4 bytes from NULL), presumably img being NULL.

The cause of the problem might be that different IDEs may set a different working directory when you run a program from the IDE, and the file doesn't happen to be in that directory. See if giving a full path to the image file helps and see if the IDE lets you set that path to wherever the executable (and the image) is.

Sorry, I replied right after I posted without checking for other posts, so...latepost
but yeah, ill try that

I did that, and I have it exiting if it didn't load (doesn't do much, but atleast it tells me what's going on). I tried adding the file - snakey.bmp - as a Resource file, but that didn't work either. It only works if i run the EXE without VS, from the debug folder.

Fixed it

It means that your app is being launched with a different working directory when being run through the debugger. This is very common.