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
Colin Barrett
I see this manifest itself (VS2012 x86) as:
"Run-Time Check Failure #0 - The value of ESP was not properly saved across a function call. This is usually a result of calling a function declared with one calling convention with a function pointer declared with a different calling convention."
in the first call to SDL_GetTicks in my application. The disassembly at the problem line is:
hires_now.QuadPart *= 1000;
00AD0792 push 0
00AD0794 push 3E8h
00AD0799 mov eax,dword ptr [ebp-10h]
00AD079C push eax
00AD079D mov ecx,dword ptr [hires_now]
00AD07A0 push ecx
00AD07A1 call _allmul (0AE7D40h)
00AD07A6 mov dword ptr [hires_now],eax
00AD07A9 mov dword ptr [ebp-10h],edx
Apparently _allmul should be popping the stack but isn't (other similar functions in SDL_stdlib.c - _alldiv and whatnot - DO pop the stack).
A 'ret 10h' at the end of _allmul appears to do the trick
All SDL_* functions are always available as real symbols, so you can always
link against them as a stable ABI. By default, however, all the things that
might have dithered down to macros in your application are now force-inlined,
to give you the same effect as before and theoretically better performance,
but still solve the classic macro problems.
Elsewhere, we provide real functions for these things that simply wrap the
inline functions, in case one needs to have a real function available.
Also: this exposed bugs: SDL_abs() does something different if you had the
macro vs the libc function, SDL_memcpy() returns a void* in the function
but not the macro, etc.
It's a long-dead platform, and we don't have any way to build for, test, or
maintain it, so there's no sense in doing acrobatics to support it.
If you need Windows CE support, use SDL 1.2. If you need Windows Phone support,
send SDL 2.0 patches for the newer Windows Mobile platform.
Even if we're blitting between two different surfaces their pixels might still overlap, because of SDL_CreateRGBSurfaceFrom(), so always use SDL_BlitCopy() and check for overlap in that function.
When handling overlapping surfaces, don't assume that memcpy() iterates forward, instead use memmove() correctly, and provide a fallback implementation of SDL_memmove() that handles the different cases.
Fixed a bug with SDL_memset() not completely filling lengths that aren't a multiple of 4.
Optimized SDL_memcpy() a bit using the same technique as SDL_memset().
John Popplewell 2009-12-08 23:05:50 PST
Originally reported by AKFoerster on the mailing list.
Error decoding UTF8 Russian text to UTF-16LE on Windows, but specifically on
platforms without iconv support (the default on Windows).
Valid UTF8 characters are flagged as being overlong and then substituted by the
UNKNOWN_UNICODE character.
After studying the testiconv.c example program, reading the RFCs and putting
some printf statements in SDL_iconv.c the problem is in a test for 'Maximum
overlong sequences', specifically 4.2.1, which is carried out by the following
code:
} else if ( p[0] >= 0xC0 ) {
if ( (p[0] & 0xE0) != 0xC0 ) {
/* Skip illegal sequences
return SDL_ICONV_EILSEQ;
*/
ch = UNKNOWN_UNICODE;
} else {
if ( (p[0] & 0xCE) == 0xC0 ) { <<<<<<<< here
overlong = SDL_TRUE;
}
ch = (Uint32)(p[0] & 0x1F);
left = 1;
}
} else {
Here is the 2-byte encoding of a character in range 00000080 - 000007FF
110xxxxx 10xxxxxx
The line in question is supposed to be checking for an overlong sequence which
would be less than
11000001 10111111
which should be represented as a single byte.
BUT, the mask value (0xCE) is wrong, it isn't checking the top-most bit:
11000001 value
11001110 mask (incorrect)
^
and should be (0xDE):
11000001 value
11011110 mask (correct)
making the above code:
} else if ( p[0] >= 0xC0 ) {
if ( (p[0] & 0xE0) != 0xC0 ) {
/* Skip illegal sequences
return SDL_ICONV_EILSEQ;
*/
ch = UNKNOWN_UNICODE;
} else {
if ( (p[0] & 0xDE) == 0xC0 ) { <<<<<<<< here
overlong = SDL_TRUE;
}
ch = (Uint32)(p[0] & 0x1F);
left = 1;
}
} else {
I can supply a test program and/or a patch if required,
best regards,
John Popplewell
Ryan C. Gordon 2009-09-19 08:25:21 PDT
This line in SDL_iconv_string (src/stdlib/SDL_iconv.c) ...
if (!fromcode || !*fromcode) {
tocode = "UTF-8";
}
Is probably supposed to assign to "fromcode" and not "tocode".
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
