Fixed bug 3710 - SDL_OpenAudio(desired, obtained) doesn't update desired's size when obtained is NULL

David Ludwig

I've created a new set of patches.  I am happy to create more, if it would help.

One version only copies 'size'.

A second version copies both 'size' and 'silence'.  When looking over the documentation for SDL_OpenAudio in SDL_audio.h, it mentioned that both 'size' and 'silence' were things that SDL_OpenAudio would calculate.

Regarding *both* patches, I did notice that SDL 1.2 appears to have always modified desired's size and silence fields.  The SDL wiki, at https://wiki.libsdl.org/SDL_OpenAudio#Remarks , does note:

src/audio/SDL_audio.c

@@ -1413,7 +1413,14 @@ SDL_OpenAudio(SDL_AudioSpec * desired, SDL_AudioSpec * obtained)
         id = open_audio_device(NULL, 0, desired, obtained,
                                SDL_AUDIO_ALLOW_ANY_CHANGE, 1);
     } else {
-        id = open_audio_device(NULL, 0, desired, NULL, 0, 1);
+        SDL_AudioSpec _obtained;
+        SDL_zero(_obtained);
+        id = open_audio_device(NULL, 0, desired, &_obtained, 0, 1);
+        /* On successful open, copy calculated values into 'desired'. */
+        if (id > 0) {
+            desired->size = _obtained.size;
+            desired->silence = _obtained.silence;
+        }
     }
 
     SDL_assert((id == 0) || (id == 1));