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| == Porting SDL applications to OS/2 == | | == Porting SDL applications to OS/2 == |
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| === Requirements ===
| | Moved to [http://www.edm2.com/index.php/SDL] |
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| To port SDL applications to OS/2, you'll need the latest SDL binaries
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| and header files from netlabs.org. Currently the OpenWatcom compiler is
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| <b>the</b> compiler for the OS/2 port of SDL, but it should also work
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| with GCC.
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| === Using the OpenWatcom compiler ===
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| There are some requirements and tricks with using the OpenWatcom compiler
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| to port SDL applications. You should note the followings things.
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| ==== Use the -ei switch for the OpenWatcom C compiler ====
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| You have to use the <i>-ei</i> switch for the OpenWatcom C compiler to
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| have the size of enums equal to the size of ints. This is a requirement of
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| SDL itself.
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| ==== Wrapping the SDL_Quit() function ====
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| The OS/2 version of SDL is compiled into a DLL file. This DLL file has all
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| the SDL functions exported by name. In order to be able to use this DLL from
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| most of the available compilers, these exports are using the <i>_Syscall</i>
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| calling convention. This leads to problems with some SDL apps, where they assume
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| that the calling convention of the API is the same as the calling convention of
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| their runtime library. For example, the following line is very usual in SDL
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| applications:
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| ...
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| atexit(SDL_Quit);
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| ...
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| This should be worked around by creating a wrapper function for SDL_Quit, and
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| using that one, this way:
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| #ifdef __WATCOMC__
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| void SDL_Quit_Wrapper()
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| {
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| SDL_Quit();
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| }
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| #endif
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| ...
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| #ifdef __WATCOMC__
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| atexit(SDL_Quit_Wrapper);
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| #else
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| atexit(SDL_Quit);
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| #endif;
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| === Using the GNU C Compiler ===
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| It was reported that some (or maybe all) of the GNU C compilers
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| (GCC) available for OS/2 can not handle the SDL.LIB file included in
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| the SDL DevPack. The problem is that the SDL.LIB file was created
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| directly from the SDL.DLL file, using the IMPLIB.EXE tool from the
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| OS/2 Developer's Toolkit, and the GCC does not recognize it to be a
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| valid library file.
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| There is a workaround, which is reported to work in this case. One has
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| to create a GCC-compatible library file (.a), using the EMXIMP tool,
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| and link against that file:
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| emximp -o sdl.imp sdl.lib
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| emximp -o sdl.a sdl.imp
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| If you plan on using SDL's multithreading capabilities (e.g. if you want
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| to include "SDL_thread.h"), be sure that enable multithreading with -Zmt
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| on your GCC commandline, otherwise you'll get an error because _beginthread()
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| and _endthread() will not be defined.
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| === General tips and tricks ===
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| ==== Morph your program to a PM program at runtime ====
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| Most SDL applications assume that they can write to STDOUT, and the user will
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| see it. In OS/2, you have to compile your application to a PM application in
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| order to be able to have a PM Window, but the STDOUT will go to NULL in this
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| case. The solution is to compile your code to a VIO application, and morph the
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| application to a PM one dynamically, at runtime, before calling SDL_Init().
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| Once you have your text output back, you might use it for showing debug messages.
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| If you do so, it's a good idea to make the STDOUT and STDERR unbuffered, so
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| the debug messages will be shown right at the time when the printf() is called,
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| so every message will be visible even in case of a crash.
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| Here is an example code on how to morph your VIO application to a PM one
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| dynamically, at runtime, and how to set STDOUT and STDERR unbuffered:
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| #define INCL_DOS
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| #include <os2.h>
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| #include <stdio.h>
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| ...
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| void MorphToPM()
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| {
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| PPIB pib;
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| PTIB tib;
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| DosGetInfoBlocks(&tib, &pib);
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| // Change flag from VIO to PM:
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| if (pib->pib_ultype==2) pib->pib_ultype = 3;
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| }
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| ...
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| int main(int argc, char *argv[])
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| {
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| MorphToPM(); // Morph the VIO application to a PM one to be able to use Win* functions
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| // Make stdout and stderr unbuffered
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| setbuf( stdout, NULL );
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| setbuf( stderr, NULL );
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| /* Initialize SDL */
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| if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
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| fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
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| exit(1);
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| }
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| ...
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