Sylvain
After a long time, I found out more clearly what was going wrong.
The native libraries should be built with a "APP_PLATFORM" as low as possible.
Ideally, APP_PLATFORM should be equals to the minSdkVersion of the AndroidManifest.xml
So that the application never runs on a lower APP_PLATFORM than it has been built for.
An additional good patch would be to write explicitly in "jni/Application.mk": APP_PLATFORM=android-10
(If no APP_PLATFORM is set, the "targetSdkVersion" of the AndroidManifest.xml is applied as an APP_PLATFORM to the native libraries. And currently, this is bad, because targetSdkVersion is 12, whereas minSdkLevel is 10.
And in fact, there is a warning from ndk: "Android NDK: WARNING: APP_PLATFORM android-12 is larger than android:minSdkVersion 10 in ./AndroidManifest.xml".)
to precise what happened in the initial reported test-case:
Let say the "c" code contains a call to "srand()".
with APP_PLATFORM=android-21, libSDL2.so contains a undef reference to "srand()".
with APP_PLATFORM=android-10, libSDL2.so contains a undef reference to "srand48()".
but srand() is missing on devices with APP_PLATFORM=android-10 (it was in fact replaced by srand48()).
So, if you build for android-21 (where srand() is available), you will really have a call to "srand()" and it will fail on android-10.
That was the issue. The path tried to fix this by in fact always calling srand48().
SDL patches that were applied are beneficial anyway, there are implicitly allowing they backward compatibility of using android-21 on a android-10 platform.
It can be helpful in case you want to target a higher APP_PLATFORM than minSdkVersion to have potentially access to more functions.
Eg you want to have access to GLES3 functions (or other) of "android-21". But, if dlopen() fails (on android-10), you do a fall-back to GLES2.
Sylvain
When using API 21 and running on an old device (android < 5.0 ?) some function are missing.
functions are (at least) : signal, sigemptyset, atof, stpcpy (strcat and strcpy), srand, rand.
Very few modifications on SDL to get this working :
on SDL
======
Undefine android configuration :
HAVE_SIGNAL
HAVE_SIGACTION
HAVE_ATOF
In "SDL_systrhead.c", comment out the few block of lines with "sigemptyset".
Android.mk:
remove the compilation of "test" directory because it contains a few rand/srand calls
Also, there are more discussions about this in internet :
https://groups.google.com/forum/#!topic/android-ndk/RjO9WmG9pfEhttp://stackoverflow.com/questions/25475055/android-ndk-load-library-cannot-locate-srand
Philipp Wiesemann 2012-09-22 05:26:11 PDT
currently SDL (HG) does not implement the power management functionality of
SDL_GetPowerInfo() for Android.
I attached a patch which tries to implement this functionality (JNI only, API
5). It supports plugged state and battery percent return values but not
remaining seconds (which are not available on Android).
- Added 'feature' enable/disable so we're not running accel/sound/whatever in Java when we don't need to be
- More work on the sound system. But it still crashes pretty horribly, not sure why yet.
