Statically linking SDL2 at compile time, rather than dynamically loading it at runtime

[absolutelynothinghere]

Is it possible to add an option for statically linking SDL2 directly into the program, along with sdl12-compat, instead of having to dynamically load SDL2 at runtime?.. That means both sdl12-compat and SDL2 are built as static libraries.

Thank you.

[smcv]

This is probably impossible, because they both want to define symbols of the same name with different meanings. Shared libraries can do this if you're very, very careful; static libraries can't.

[madebr]

This will probably also never work, unless you rename all SDL3 symbols such that they do not conflict with SDL2.
Changing the SDL3 sources to support this, will not be accepted.

Is there a way to change all symbol names in a static archive?
Then, it is perhaps possible to prefix all symbols in libSDL3.a with SDL3_?

[madebr]

Not for sdl12-compat, but for sdl2-compat

I just managed to link a sdl2 project to a static sdl2-compat and static SDL3.
What I did:

1. Using nm on libSDL3.a, create a header that prefixes all defined symbols with SDL3_renamed_. This results in a header like:

   #define ActivateMotionPlus SDL3_renamed_ActivateMotionPlus
   #define ActivateMotionPlusWithMode SDL3_renamed_ActivateMotionPlusWithMode
   ...

2. Configure and build SDL3 with -DCMAKE_C_FLAGS="-include SDL3_renames.h" -DSDL_STATIC=ON -DSDL_SHARED=ON
   (ignore the warnings about dynapi)

3. Configure and build a patched sdl2-compat with -DSDL2COMPAT_STATIC=1 -DCMAKE_C_FLAGS="-DSTATIC_SDL3".

   sdl2-compat patch to use renamed SDL3 symbols

   diff --git a/CMakeLists.txt b/CMakeLists.txt
   index eb8a0e5..349656e 100644
   --- a/CMakeLists.txt
   +++ b/CMakeLists.txt
   @@ -217,7 +217,7 @@ endif()
    add_library(SDL2 SHARED ${SDL2COMPAT_SRCS})
    add_library(SDL2::SDL2 ALIAS SDL2)
    SDL_AddCommonCompilerFlags(SDL2 WERROR "${SDL2COMPAT_WERROR}")
   -target_link_libraries(SDL2 PRIVATE $<BUILD_INTERFACE:SDL3::Headers>)
   +target_link_libraries(SDL2 PRIVATE $<BUILD_INTERFACE:SDL3::Headers> SDL3::SDL3-static)
    target_include_directories(SDL2
      INTERFACE
        "$<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/include>"
   @@ -407,7 +407,7 @@ if(SDL2COMPAT_STATIC)
      add_library(SDL2-static STATIC ${SDL2COMPAT_SRCS})
      add_library(SDL2::SDL2-static ALIAS SDL2-static)
      SDL_AddCommonCompilerFlags(SDL2-static WERROR "${SDL2COMPAT_WERROR}")
   -  target_link_libraries(SDL2-static PRIVATE $<BUILD_INTERFACE:SDL3::Headers>)
   +  target_link_libraries(SDL2-static PRIVATE $<BUILD_INTERFACE:SDL3::Headers>  SDL3::SDL3-static)
      target_include_directories(SDL2-static
        INTERFACE
          "$<BUILD_INTERFACE:${PROJECT_BINARY_DIR}/include>"
   diff --git a/src/sdl2_compat.c b/src/sdl2_compat.c
   index 7327b89..0a5e0d6 100644
   --- a/src/sdl2_compat.c
   +++ b/src/sdl2_compat.c
   @@ -120,6 +120,12 @@ This breaks the build when creating SDL_ ## DisableScreenSaver
    extern "C" {
    #endif
    
   +#if defined(STATIC_SDL3)
   +#define SDL3_SYM(rc,fn,params,args,ret) \
   +    rc SDLCALL SDL3_renamed_SDL_##fn params;
   +#include "sdl3_syms.h"
   +#endif
   +
    /** Define SDL2COMPAT_TEST_SYMS=1 to have warnings about wrong prototypes of src/sdl3_sym.h
     *  It won't compile but it helps to make sure it's sync'ed with SDL3 headers.
     */
   @@ -244,11 +250,25 @@ SDL2COMPAT_itoa(char *dst, int val)
        } while (ptr > dst);
    }
    
   +#if defined(__unix__)
   +#include <dlfcn.h>
   +#endif
    
    /* Obviously we can't use SDL_LoadObject() to load SDL3.  :)  */
    /* FIXME: Updated library names after https://github.com/libsdl-org/SDL/issues/5626 solidifies.  */
    static char loaderror[256];
   -#if defined(_WIN32)
   +#if defined(STATIC_SDL3)
   +    static int Loaded_SDL3 = 0;
   +    #if defined(_WIN32)
   +        #define DIRSEP "\\"
   +    #else
   +        #define DIRSEP "/"
   +    #endif
   +    #define SDL3_LIBNAME Must_Be_Unused
   +    #define LoadSDL3Library()  (Loaded_SDL3 = 1)
   +    #define LookupSDL3Sym(sym) (void *)SDL3_renamed_SDL_##sym
   +    #define CloseSDL3Library() do { Loaded_SDL3 = 0; } while (0)
   +#elif defined(_WIN32)
        static HMODULE Loaded_SDL3 = NULL;
        #define DIRSEP "\\"
        #define SDL3_LIBNAME "SDL3.dll"
   @@ -329,6 +349,7 @@ static char loaderror[256];
    static int SDL2Compat_InitOnStartup(void);
    
    
   +#if !defined(STATIC_SDL3)
    static void *
    LoadSDL3Symbol(const char *fn, bool *okay)
    {
   @@ -343,6 +364,7 @@ LoadSDL3Symbol(const char *fn, bool *okay)
        }
        return retval;
    }
   +#endif
    
    static void
    UnloadSDL3(void)
   @@ -630,7 +652,11 @@ LoadSDL3(void)
            if (!okay) {
                SDL2COMPAT_stpcpy(loaderror, "Failed loading SDL3 library.");
            } else {
   +#if defined(STATIC_SDL3)
   +            #define SDL3_SYM(rc,fn,params,args,ret) SDL3_##fn = (SDL3_##fn##_t) SDL3_renamed_SDL_##fn;
   +#else
                #define SDL3_SYM(rc,fn,params,args,ret) SDL3_##fn = (SDL3_##fn##_t) LoadSDL3Symbol("SDL_" #fn, &okay);
   +#endif
                #include "sdl3_syms.h"
                if (okay) {
                    const int sdl3version = SDL3_GetVersion();
   diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
   index 03f86f5..22ff7e0 100644
   --- a/test/CMakeLists.txt
   +++ b/test/CMakeLists.txt
   @@ -28,7 +28,7 @@ function(test_program NAME)
      list(APPEND SDL2COMPAT_TEST_EXECUTABLES ${NAME})
      set(SDL2COMPAT_TEST_EXECUTABLES ${SDL2COMPAT_TEST_EXECUTABLES} PARENT_SCOPE)
      SDL_AddCommonCompilerFlags(${NAME} WERROR "${SDL2COMPAT_WERROR}")
   -  target_link_libraries(${NAME} PRIVATE SDL2::SDL2main SDL2::SDL2test SDL2::SDL2)
   +  target_link_libraries(${NAME} PRIVATE SDL2::SDL2main SDL2::SDL2test SDL2::SDL2-static)
      # Turn off MSVC's aggressive C runtime warnings for the old test programs.
      if(MSVC)
        target_compile_definitions(${NAME} PRIVATE ${HAVE_OPENGL_DEFINE} _CRT_SECURE_NO_WARNINGS _CRT_SECURE_NO_DEPRECATE _CRT_NONSTDC_NO_DEPRECATE)
   

It goes without saying that this configuration is 100% unsupported.