[macos] SDL 2.24.2 - SDL.h #includes <SDL2/(various)> but there is no SDL2 subdirectory

[nbriggs]

For example:

In file included from ../src/sdl.c:1:
/Library/Frameworks/SDL2.framework/Headers/SDL.h:32:10: fatal error: 'SDL2/SDL_main.h' file not found
#include <SDL2/SDL_main.h>
         ^~~~~~~~~~~~~~~~~
1 error generated.

but, all the include files are at the same level in Headers/

% ls /Library/Frameworks/SDL2.framework/Versions/A/Headers/
SDL.h				SDL_keyboard.h			SDL_power.h
SDL_assert.h			SDL_keycode.h			SDL_quit.h
SDL_atomic.h			SDL_loadso.h			SDL_rect.h
SDL_audio.h			SDL_locale.h			SDL_render.h
SDL_bits.h			SDL_log.h			SDL_revision.h
SDL_blendmode.h			SDL_main.h			SDL_rwops.h
SDL_clipboard.h			SDL_messagebox.h		SDL_scancode.h
SDL_config.h			SDL_metal.h			SDL_sensor.h
SDL_config_macosx.h		SDL_misc.h			SDL_shape.h
SDL_copying.h			SDL_mouse.h			SDL_stdinc.h
SDL_cpuinfo.h			SDL_mutex.h			SDL_surface.h
SDL_endian.h			SDL_name.h			SDL_system.h
SDL_error.h			SDL_opengl.h			SDL_syswm.h
SDL_events.h			SDL_opengl_glext.h		SDL_thread.h
SDL_filesystem.h		SDL_opengles.h			SDL_timer.h
SDL_gamecontroller.h		SDL_opengles2.h			SDL_touch.h
SDL_gesture.h			SDL_opengles2_gl2.h		SDL_types.h
SDL_guid.h			SDL_opengles2_gl2ext.h		SDL_version.h
SDL_haptic.h			SDL_opengles2_gl2platform.h	SDL_video.h
SDL_hidapi.h			SDL_opengles2_khrplatform.h	SDL_vulkan.h
SDL_hints.h			SDL_pixels.h			begin_code.h
SDL_joystick.h			SDL_platform.h			close_code.h

One fix to enable compilation is to symlink SDL2 -> .

[FtZPetruska]

I have seen a similar issue that boiled down to incorrect CMake configuration.

When using SDL2 as a framework, clang needs to be passed the -framework SDL2 option to properly set include path (prefix all the files in Headers with the name of the framework). As such your CMake target needs to link with SDL2::SDL2 even if it only needs the headers. Setting the target include directories alone will not work.

[madebr]

You should be able to only add the headers by doing:

target_include_directories(your_game PRIVATE $<TARGET_PROPERTY:SDL2::SDL2,INCLUDE_DIRECTORIES>)

[madebr]

Would making available a SDL2::Headers target be useful?

[nbriggs]

The CMakeLists.txt that I've inherited, in its SDL2 related pieces, does:

  FIND_PACKAGE(SDL2 REQUIRED)
...
  TARGET_INCLUDE_DIRECTORIES(xxx PRIVATE ${SDL2_INCLUDE_DIRS})
  TARGET_LINK_LIBRARIES(xxx ${SDL2_LIBRARIES})

where the SDL2_... appear to be provided by the SDL2 package. So that's probably just wrong for the macOS framework case. What's the right way to configure it to cope with both a typical Linux installation of SDL2 and the macOS framework case?

[madebr]

I was taught the only guaranteed working way to include the SDL headers is by doing the following, without a SDL2/ prefix.

#include "SDL.h"

This is also in line with sdl2-config.
Running sdl2-config --cflags on my system returns: -I/usr/include/SDL2 -D_REENTRANT.
The addition of the includedir to sdl2.pc was done only recently.

[nbriggs]

The above CMakeLists.txt fragments result in CMake compiling with:

[...]/usr/bin/cc -DRELEASE=351 -DSDL  -isystem /Library/Frameworks/SDL2.framework/Headers -O3 -DNDEBUG -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk -mmacosx-version-min=11.7 -F /Library/Frameworks/ -std=gnu99 -MD -MT CMakeFiles/ldesdl.dir/src/sdl.c.o -MF CMakeFiles/ldesdl.dir/src/sdl.c.o.d -o CMakeFiles/ldesdl.dir/src/sdl.c.o -c /Users/briggs/Projects/maiko/src/sdl.c

and linking with:

[...]/usr/bin/cc -O3 -DNDEBUG -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk -mmacosx-version-min=11.7 -Wl,-search_paths_first -Wl,-headerpad_max_install_names -F /Library/Frameworks/ -framework SDL2 [all the object files] -o ldesdl  -lm 

so it's pointing at the Headers to include, and the framework to link...

[FtZPetruska]

I was taught the only guaranteed working way to include the SDL headers is by doing the following, without a SDL2/ prefix.

#include "SDL.h"

This is also in line with sdl2-config. Running sdl2-config --cflags on my system returns: -I/usr/include/SDL2 -D_REENTRANT. The addition of the includedir to sdl2.pc was done only recently.

Apple's frameworks are a special case where you need to prefix the includes with SDL2/ despite not being actually being layed out this way.

If you look at the framework's SDL.h, it includes other headers this way:

#include <SDL2/SDL_main.h>
#include <SDL2/SDL_stdinc.h>
....

Whereas on a more typical release, SDL.h includes the headers as expected:

#include "SDL_main.h"
#include "SDL_stdinc.h"
...

Would making available a SDL2::Headers target be useful?

Not necessarily, for clang to properly include a framework (even to just get correct includes) it needs to be passed a -framework SDL2, if INTERFACE_INCLUDE_DIRECTORIES behaves the same as INTERFACE_LINK_OPTIONS what could be put is:

set_target_properties(SDL2::SDL2
        PROPERTIES
            INTERFACE_COMPILE_OPTIONS "SHELL:-F \"${SDL2_FRAMEWORK_PARENT_PATH}\""
            INTERFACE_INCLUDE_DIRECTORIES "SHELL:-F \"${SDL2_FRAMEWORK_PARENT_PATH}\";SHELL:-framework SDL2"
            INTERFACE_LINK_OPTIONS "SHELL:-F \"${SDL2_FRAMEWORK_PARENT_PATH}\";SHELL:-framework SDL2"
            COMPATIBLE_INTERFACE_BOOL "SDL2_SHARED"
            INTERFACE_SDL2_SHARED "ON"
    )

And then set SDL2_INCLUDE_DIR to SDL2::SDL2 similar to how SDL2_LIBRARIES just contains SDL2::SDL2.

EDIT: Nevermind, that does not work.

[FtZPetruska]

After further investigating, here are the findings:

• It is the -F /Path/To/Frameworks/ option that add the proper include for frameworks.
• Setting INTERFACE_INCLUDE_DIRECTORIES to /Path/To/SDL2.framework/Headers allows for the end-user to just #include "SDL.h", then the rest of the headers will be found through the option above.

Moreover, checking the pull request @nbriggs linked above, I wasn't able to reproduce the issue, building and linking just fine with the latest Framework alone.

[madebr]

Thanks, I was just able to mount the .dmg on Linux with this fuse module.

I didn't know the framework's SDL.h was including other headers through SDL2/....
That means the framework's sdl2-config.cmake is missing an include path.

I think the following patch addresses this. Can someone check?

--- a/Xcode/SDL/pkg-support/resources/CMake/sdl2-config.cmake
+++ b/Xcode/SDL/pkg-support/resources/CMake/sdl2-config.cmake
@@ -39,7 +39,7 @@ string(REGEX REPLACE "SDL2\\.framework.*" "" SDL2_FRAMEWORK_PARENT_PATH "${CMAKE
 set_and_check(SDL2_PREFIX       "${SDL2_FRAMEWORK_PATH}")
 set_and_check(SDL2_EXEC_PREFIX  "${SDL2_FRAMEWORK_PATH}")
 set_and_check(SDL2_INCLUDE_DIR  "${SDL2_FRAMEWORK_PATH}/Headers")
-set(SDL2_INCLUDE_DIRS           "${SDL2_INCLUDE_DIR}")
+set(SDL2_INCLUDE_DIRS           "${SDL2_INCLUDE_DIR};${SDL2_FRAMEWORK_PATH}")
 set_and_check(SDL2_BINDIR       "${SDL2_FRAMEWORK_PATH}")
 set_and_check(SDL2_LIBDIR       "${SDL2_FRAMEWORK_PATH}")
 
@@ -53,7 +53,7 @@ if(NOT TARGET SDL2::SDL2)
     set_target_properties(SDL2::SDL2
         PROPERTIES
             INTERFACE_COMPILE_OPTIONS "SHELL:-F \"${SDL2_FRAMEWORK_PARENT_PATH}\""
-            INTERFACE_INCLUDE_DIRECTORIES "${SDL2_INCLUDE_DIR}"
+            INTERFACE_INCLUDE_DIRECTORIES "${SDL2_INCLUDE_DIRS}"
             INTERFACE_LINK_OPTIONS "SHELL:-F \"${SDL2_FRAMEWORK_PARENT_PATH}\";SHELL:-framework SDL2"
             COMPATIBLE_INTERFACE_BOOL "SDL2_SHARED"
             INTERFACE_SDL2_SHARED "ON"

[nbriggs]

That seems to do it -- I applied that patch, removed my symlink SDL2 => . from the Headers, reconfigured, and recompiled. Typical compile step now looks like:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc \
 -DRELEASE=351 \
 -DSDL \
 -I/Users/briggs/Projects/maiko/inc \
 -isystem /Library/Frameworks/SDL2.framework/Headers \
 -iframework /Library/Frameworks \
 -fno-strict-aliasing  \
 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk \
 -mmacosx-version-min=11.7 \
 -F /Library/Frameworks/ \
 -std=gnu99 \
 -MD \
 -MT CMakeFiles/ldesdl.dir/src/sdl.c.o \
 -MF CMakeFiles/ldesdl.dir/src/sdl.c.o.d \
 -o CMakeFiles/ldesdl.dir/src/sdl.c.o \
 -c /Users/briggs/Projects/maiko/src/sdl.c

So, +1 for that. Thanks!

[madebr]

Applied in e6c4db8

Can this issue be considered fixed?

[nbriggs]

I'm good with that, perhaps @FtZPetruska will also have an opinion.

[FtZPetruska]

Tried the framework with the patch, it compiles my projects with no issues. So I'm good with it too!

[madebr]

Good to hear!

Strange to see the compile command in #6513 (comment) not containing

-I/Library/Frameworks/SDL2.framework

[nbriggs]

@madebr not so strange, I think -- it has -isystem /Library/Frameworks/SDL2.framework/Headers to add that directory to the system include search path.

[madebr]

But my patch was adding the framework root folder, e.g. /Library/Frameworks/SDL2.framework.

[nbriggs]

Without the patch it does:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc \
 -DRELEASE=351 \
 -DSDL \
 -I/Users/briggs/Projects/maiko/inc \
 -isystem /Library/Frameworks/SDL2.framework/Headers \
 -fno-strict-aliasing  \
 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk \
 -mmacosx-version-min=11.7 \
 -F /Library/Frameworks/ \
 -std=gnu99 \
 -MD \
 -MT CMakeFiles/ldesdl.dir/src/sdl.c.o \
 -MF CMakeFiles/ldesdl.dir/src/sdl.c.o.d \
 -o CMakeFiles/ldesdl.dir/src/sdl.c.o \
 -c /Users/briggs/Projects/maiko/src/sdl.c

and what's missing here is the -iframework /Library/Frameworks

BUT... I'm really confused - I put the sdl2-config.cmake back to the way it was, cleared everything redid the "cmake ..", and I can't reproduce the original problem!

[madebr]

Closing this issue as the original issue has been resolved.