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Bug 4393

Summary: Linux build fails with --disable-threads
Product: SDL Reporter: Daniel Scharrer <daniel>
Component: threadAssignee: Ryan C. Gordon <icculus>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: fontaine.fabrice, icculus, sezeroz
Version: 2.0.9   
Hardware: x86_64   
OS: Linux   
Attachments: fix build with --disable-threads

Description Daniel Scharrer 2018-11-20 04:04:22 UTC 
$ ./configure --disable-threads
$ make
[...]
  LTLINK build/libSDL2.la
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: build/.libs/SDL_dynapi.o: in function `initialize_jumptable':
/home/dscharrer/SDL2-2.0.9/src/dynapi/SDL_dynapi_procs.h:34: undefined reference to `SDL_LinuxSetThreadPriority_REAL'
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: build/.libs/SDL_waylanddatamanager.o: in function `write_pipe':
/home/dscharrer/SDL2-2.0.9/src/video/wayland/SDL_waylanddatamanager.c:56: undefined reference to `pthread_sigmask'
/usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../x86_64-pc-linux-gnu/bin/ld: /home/dscharrer/SDL2-2.0.9/src/video/wayland/SDL_waylanddatamanager.c:73: undefined reference to `pthread_sigmask'
collect2: error: ld returned 1 exit status
make: *** [Makefile:147: build/libSDL2.la] Error 1
Comment 1 Fabrice Fontaine 2018-11-23 21:20:19 UTC 
Created attachment 3502 [details]
fix build with --disable-threads
Comment 2 Fabrice Fontaine 2018-11-23 21:21:55 UTC 
This issue is raised by SDL_LinuxSetThreadPriority() which has been added since version 2.0.9 and https://github.com/SDL-mirror/SDL/commit/f25a7fa870bdceb339e5105973f689606bcb9086

This function is used in src/dynapi/SDL_dynapi_procs.h even
when SDL_THREADS_DISABLED

However, when SDL_THREADS_DISABLED is set, SDL_LinuxSetThreadPriority is
not defined because thread/pthread/SDL_systhread.c is not built

So SDL_THREADS_DISABLED should be checked in addition to __LINUX__ (see attachment for a patch)

Fixes:
 - http://autobuild.buildroot.org/results/539cb9ab6c605dc6be73ebe90debab1a998f2451
Comment 3 Ryan C. Gordon 2018-11-23 22:21:45 UTC 
(In reply to Fabrice Fontaine from comment #2)
> This function is used in src/dynapi/SDL_dynapi_procs.h even
> when SDL_THREADS_DISABLED

This needs to be in SDL_dynapi_procs.h even if the subsystem is disabled; the function must still exist for binary compatibility, but it can just "return SDL_Unsupported();" or whatever if threads are disabled.

--ryan.
Comment 4 Ryan C. Gordon 2018-12-01 15:37:37 UTC 
This is fixed in https://hg.libsdl.org/SDL/rev/fa17d3d76431, thanks!

--ryan.
Comment 5 Ozkan Sezer 2018-12-03 06:41:55 UTC 
New warning:

In file included from src/thread/pthread/../../SDL_internal.h:45:0,
                 from src/thread/pthread/SDL_systhread.c:22:
src/thread/pthread/SDL_systhread.c: In function 'SDL_SYS_SetThreadPriority':
src/thread/pthread/../../dynapi/SDL_dynapi_overrides.h:673:36: warning: implicit declaration of function 'SDL_LinuxSetThreadPriority_REAL'; did you mean 'SDL_SetThreadPriority_REAL'? [-Wimplicit-function-declaration]
 #define SDL_LinuxSetThreadPriority SDL_LinuxSetThreadPriority_REAL
                                    ^
src/thread/pthread/SDL_systhread.c:206:12: note: in expansion of macro 'SDL_LinuxSetThreadPriority'
     return SDL_LinuxSetThreadPriority(thread, value);
            ^~~~~~~~~~~~~~~~~~~~~~~~~~
Comment 6 Ryan C. Gordon 2018-12-03 07:17:00 UTC 
I have this fixed locally, will clean up and commit in the morning.

--ryan.
Comment 7 Ryan C. Gordon 2019-03-01 00:14:48 UTC 
(In reply to Ryan C. Gordon from comment #6)
> I have this fixed locally, will clean up and commit in the morning.

...and I did, but forgot to resolve this bug.

Fixed in https://hg.libsdl.org/SDL/rev/f8041c025fd3 and https://hg.libsdl.org/SDL/rev/5d56e3a2a3e4

--ryan.