Possible API/ABI incompatibility with SDL2-ttf

[Manuel A. Fernandez Montecelo]

Hi,

We're more than halfway there upgrading packages of the latest
upstream releases to Debian.

When reviewing the changes to the -ttf module, I noticed the diff below.

I don't think that the change of arguments in TTF_GetFontKerningSize()
is ABI compatible, specially in not-so-mainstream architectures, or
with big endian architectures (and we have a bunch of those).

Even if the caller has to provide a parameter which is big enough in
the old ABI, maybe the new code of -ttf would modify bits of the
memory space of the bigger variable that then the caller doesn't
interpret correctly (it reads a number which is different from the
correct one).

There are several packages of Debian using that code:

  https://codesearch.debian.net/perpackage-results/TTF_GetFontKerningSize/2/page_0

Can you please review and comment?


===============================
diff --git a/SDL_ttf.h b/SDL_ttf.h
index 1c7a801..f79bd90 100644
--- a/SDL_ttf.h
+++ b/SDL_ttf.h
@@ -1,6 +1,6 @@
 /*
   SDL_ttf:  A companion library to SDL for working with TrueType (tm) fonts
-  Copyright (C) 2001-2013 Sam Lantinga <slouken at libsdl.org>
+  Copyright (C) 2001-2016 Sam Lantinga <slouken at libsdl.org>

   This software is provided 'as-is', without any express or implied
   warranty.  In no event will the authors be held liable for any damages
@@ -39,7 +39,7 @@ extern "C" {
 */
 #define SDL_TTF_MAJOR_VERSION   2
 #define SDL_TTF_MINOR_VERSION   0
-#define SDL_TTF_PATCHLEVEL      12
+#define SDL_TTF_PATCHLEVEL      13

 /* This macro can be used to fill a version structure with the compile-time
  * version of the SDL_ttf library.
@@ -248,7 +248,7 @@ extern DECLSPEC void SDLCALL TTF_Quit(void);
 extern DECLSPEC int SDLCALL TTF_WasInit(void);

 /* Get the kerning size of two glyphs */
-extern DECLSPEC int TTF_GetFontKerningSize(TTF_Font *font, int
prev_index, int index);
+extern DECLSPEC int TTF_GetFontKerningSize(TTF_Font *font, Uint16
previous_ch, Uint16 ch);

 /* We'll use SDL for reporting errors */
 #define TTF_SetError    SDL_SetError

===============================


-- 
Manuel A. Fernandez Montecelo <manuel.montezelo at gmail.com>