This bug report was migrated from our old Bugzilla tracker.

These attachments are available in the static archive:

• IMG_png warnings patch (20.patch, text/plain, 2018-10-13 12:20:06 +0000, 8206 bytes)

Reported in version: unspecified
Reported for operating system, platform: All, All

Comments on the original bug report:

On 2018-10-13 12:20:06 +0000, Ozkan Sezer wrote:

Created attachment 3371
IMG_png warnings patch

When building against libpng-1.4/1.5 with --disable-png-shared, warnings
are emitted:
I20/IMG_png.c:145: warning: assignment from incompatible pointer type
I20/IMG_png.c:146: warning: assignment from incompatible pointer type
I20/IMG_png.c:147: warning: assignment from incompatible pointer type
I20/IMG_png.c:148: warning: assignment from incompatible pointer type

Some libpng functions take non-const args in 1.2..1.5, but take const
args in 1.6. To make it worse, some funcs, e.g. png_get_PLTE(), take
const args in 1.4..1.5 but take non-const args in 1.6+, like:
1.4/1.5: (png_const_structp , png_const_infop, png_colorp *, int *)
1.6/1.7: (png_const_structrp, png_inforp , png_colorp *, int *)

I came up with the following quick'n'dirty patch, which adds noconst15
and noconst16 to affected function pointer typedefs:
noconst15: version < 1.6 doesn't have const, >= 1.6 adds it
noconst16: version < 1.6 does have const, >= 1.6 removes it

Should I apply, or should we live with the warnings (which would break
builds if one uses -Werror) ?

On 2018-10-23 20:01:18 +0000, Ozkan Sezer wrote:

Went ahead and applied this:
http://hg.libsdl.org/SDL_image/rev/89225c8816d6
http://hg.libsdl.org/SDL_image/rev/fa3c53a205a9