We are currently migrating Bugzilla to GitHub issues.
Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.
When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.

Is it expected behaviour for

SDL_BlitSurface(source, 0, target, 0);

to increment the refcount of target? Just because I’ve blitted source to target does that necessarily mean that target ‘has a reference’ to source?

(As I call FreeSurface on my source~s the refcount of target does decrease)

Here is a simple demonstration


#include "SDL.h"

void test(int x)
{
    SDL_Surface *image1 = SDL_CreateRGBSurface(0, 100,100, 32, 0, 0, 0, 0);
    SDL_Surface *image2 = SDL_CreateRGBSurface(0, 100,100, 32, 0, 0, 0, 0);
    printf("%d load: image1 %d image2 %d\n", x, image1->refcount, image2->refcount);
    SDL_BlitSurface(image1, 0, image2, 0);
    printf("%d blit: image1 %d image2 %d\n", x, image1->refcount, image2->refcount);
    if (x == 0)
    {
        SDL_FreeSurface(image1);
        SDL_FreeSurface(image2);
    }
    else
    {
        SDL_FreeSurface(image2);
        SDL_FreeSurface(image1);
    }
    printf("%d free: image1 %d image2 %d\n", x, image1->refcount, image2->refcount);
}

int main(int argc, char* argv[])
{
    test(0);
    test(1);
}

Compile with

g++ -o sdleg3 sdleg3.c -LSDL2 -I/usr/include/SDL2 -lSDL2

Output is

0 load: image1 1 image2 1
0 blit: image1 1 image2 2
0 free: image1 0 image2 0
1 load: image1 1 image2 1
1 blit: image1 1 image2 2
1 free: image1 0 image2 -1

So deleting the target surface first leads to a refcount of -1