You might already know this, but android debugging from gdb is now really, really easy - if you can stomach gdb!
See Android/ndk6/docs/NDK-GDB.html in your NDK documentation.
Basically, the app's libs/armeabi folder must have a gdbserver in it... which is put there automatically by the ndk-build command (remember not to ship your app with gdbserver in it!):
So...: build your app, install with e.g.:
adb install -r myfile.apk
Start your app directly from the Android UI, and in a terminal, change to your product's jni folder, and you're ready to debug!
Using command-line gdb
If you prefer command-line gdb, type this:
You'll find that ndk-gdb will break as your app attaches. Set a breakpoint if you want (optional!), e.g.:
Enter "cont" to continue...
And the debugger will now hit your breakpoints - use normal gdb commands to control it!
Using the graphical ddd debugger
If, like me, you prefer to use a graphical debugger, it is really easy to use ddd as a wrapper around gdb!
Many thanks to a blog reader for this suggestion!
It is really easy to use ddd instead... here are the steps!
1. Install ddd ...!
2. Modify your ndk-gdb shells script, to simply comment-out the "exit 1" call when an unexpected argument is passed
Start your app from Eclipse
In a terminal window, change to your project's jni folder (if you're not there already!)
Run ddd like this - and that is all there is to it!
ddd --debugger ndk-gdb
Using gdb for JNI/NDK from Eclipse is way too painful - I wouldn't bother. :)
On a final note, you can use this code to force a breakpoint at runtime...
#define BREAKPOINT __asm__ ("bkpt 0")
printf ("Hitting breakpoint!");
printf ("Gone past breakpoint!");