Include guards in most changed files were missing, I added them keeping
the same style as other SDL files. In some cases I moved the include
guards around to be the first thing the header has to take advantage of
any possible improvements compiler may have for inclusion guards.
Vitaly Novichkov
Once I ran build of my codecs collection on AppVeyor where my CMake script downloads latest SDL2 from HG repo, failed to link because of math functions conflict:
https://ci.appveyor.com/project/Wohlstand/audiocodecs/build/1.0.44
The revision is b94292eebb5c
There are both vanilla MinGW and MinGW-w64 are failed to build.
```
[100%] Linking C shared library libSDL2.dll
c:/mingw/bin/../lib/gcc/mingw32/5.3.0/../../../libmingwex.a(scalbn.o):(.text+0x0): multiple definition of `scalbln'
CMakeFiles\SDL2.dir/objects.a(s_scalbn.c.obj):C:/projects/audiocodecs/build-MinGW-Release-Win32/external/SDL2/src/SDL2HG/src/libm/s_scalbn.c:30: first defined here
(Most of its complaints here are that these ints can be negative, although
they wouldn't been in sane cases. Checking sanity is what assertions do, and
it placates the analyzer appropriately.)
Having the SDL functions inline is causing build issues, and in the case of malloc(), etc. causing malloc/free mismatches, if the application build environment differs from the SDL build environment.
In the interest of safety and consistency, the functions will always be in the SDL library and will only be redirected to the C library there, if they are available.
See the following threads on the SDL mailing list for the gruesome details:
* SDL_stdinc.h inlines problematic when application not compiled in exact same feature environment
* Error compiling program against SDL2 with -std=c++11 g++ flag
Daniele Forghieri 2009-09-30 15:40:53 PDT
To compile the source in libm the variable huge must be renamed, I choose
huge_val
The patch attached change it so it compiles
Betreff: [SDL] [PATCH] Make static variables const
Datum: Tue, 19 May 2009 19:45:37 +0200
Hi,
this is a set of simple changes which make some of SDL's internal static
arrays constant. The purpose is to shrink the number of write-able
static bytes and thus increase the number of memory pages shared between
SDL applications.
The patch set is against trunk@4513. Each of the attached patch files is
specific to a sub-system. The set is completed by a second mail, because
of the list's 40 KiB limit.
The files readelf-r4513.txt and readelf-const-patch.txt where made by
calling 'readelf -S libSDL.so'. They show the difference in ELF sections
without and with the patch. Some numbers measured on my x86-64:
Before
[13] .rodata PROGBITS 00000000000eaaa0 000eaaa0
0000000000008170 0000000000000000 A 0 0 32
[19] .data.rel.ro PROGBITS 00000000003045e0 001045e0
00000000000023d0 0000000000000000 WA 0 0 32
[23] .data PROGBITS 00000000003076e0 001076e0
0000000000004988 0000000000000000 WA 0 0 32
After
[13] .rodata PROGBITS 00000000000eaaa0 000eaaa0
0000000000009a50 0000000000000000 A 0 0 32
[19] .data.rel.ro PROGBITS 0000000000306040 00106040
0000000000002608 0000000000000000 WA 0 0 32
[23] .data PROGBITS 0000000000309360 00109360
0000000000002e88 0000000000000000 WA 0 0 32
The size of the write-able data section decreased considerably. Some
entries became const-after-relocation, while most of its content went
straight into the read-only data section.
Best regards, Thomas
