understanding virtual functions

http://jovechia.blogspot.com/2009/02/how-g-implement-virtual-function.html

using gdbserver on android emulator

1. Make your library debugable (add -g options in makefile)
modify your Android.mk add below command "LOCAL_CPPFLAGS += -g" for C++ files and "LOCAL_CFLAGS += -G" FOR C files.
rebuild your library and system image(if necessary)

2. in your local system redirect the debug port
$ telnet localhost 5554
redir add tcp:1234:1234
exit

3.you can start emulator by below command with debug port redirected.
./emulator -avd avdname -qemu -redir udp:1234::1234

4. push gdbserver to emulator
adb push ./out/target/product/generic/obj/EXECUTABLES/gdbserver_intermediates/gdbserver /system/bin/

5. run # gdbserver :1234 --attach your-desired-pid or gdbserver :1234 desired_process

6. run ./prebuilt/linux-x86/toolchain/arm-eabi-4.2.1/bin/arm-eabi-gdb ./out/target/product/generic/symbols/system/bin/app_process

7. in gdb-terminal
gdb>set solib-search-path out/target/product/generic/symbols/system/lib
In case there are multiple library paths to be searched, use ':' to concatenate the paths
gdb>target remote localhost:1234

8. Now you can see the Errors .... Happy remote Debugging!!!!

Common Error:

Malformed packet(b) (missing colon): re:0;
Packet: 'T050b:00000000;0d:c03ecebe;0f:b0070040;thread:4ab;core:0;'

This means the gdbserver and gdb in localhost are not compatible!!

linux-android cross-compiling EGL surafce

Here is a simple HelloWorld EGL prog tat creates android window and displays openGL ES Surface

http://jiggawatt.org/badc0de/android/
(main.c)

Here is a Android.mk file for cross compiling this with NDK

LOCAL_PATH:=$(call my-dir)
include $(CLEAR_VARS)
LOCAL_ARM_MODE:=arm
LOCAL_MODULE:=mini
LOCAL_SRC_FILES:=main.c
LOCAL_MODULE_TAGS:=eng debug
LD_LIBRARY_PATH:=/home/shivram/android-ndk-r6b/platforms/android-14/arch-arm/usr/lib
LOCAL_LDLIBS:=\
-L/home/shivram/android-ndk-r6b/platforms/android-14/arch-arm/usr/lib \
-lEGL \
-ldl \
-lsurfaceflinger \
-lhardware \
-lhardware_legacy \
-lpixelflinger \
-lwpa_client \
-lemoji \
-lnetutils \
-ljpeg \
-lc \
-llog \
-lexpat \
-lskia \
-lui \
-lcutils \
-lutils \
-lbinder \
-lsurfaceflinger_client \
-lGLESv1_CM
LD:=/home/shivram/android-ndk-r6b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-ld
LOCAL_SHARED_LIBRARIES:=\
EGL \
GLESv1_CM
LOCAL_CFLAGS := \
-DHAVE_CONFIG_H \
-I/home/shivram/android-ndk-r6b/platforms/android-14/arch-arm/usr/include \
-I/home/shivram/android-ndk-r6b/platforms/android-14/arch-arm/usr/include/EGL \
-I/home/shivram/android-ndk-r6b/platforms/android-14/arch-arm/usr/include/GLES \
-DG_THREADS_MANDATORY \
-DG_DISABLE_DEPRECATED \
-Wall \
-Wdeclaration-after-statement \
-Wvla \
-Wpointer-arith \
-Wmissing-declarations \
-Wmissing-prototypes \
-Wredundant-decls \
-Wundef \
-Wwrite-strings \
-Wformat-nonliteral \
-Wformat-security \
-Wold-style-definition \
-Winit-self \
-Wmissing-include-dirs \
-Waddress \
-Waggregate-return \
-Wno-multichar \
-Wnested-externs \
-g \
-nostdlib \
-Bdynamic \
-Wl,-dynamic-linker,/system/bin/linker \
-Wl,--gc-sections \
-Wl,-z,nocopyreloc \
-DGST_DISABLE_DEPRECATED
include $(BUILD_EXECUTABLE)

When we try to compile this.. we get... undefined reference to some pthread functions

To resolve this, the key is to write a wrapper or define those missing functions in ur (main.c) code ;)

Building GStreamer for Android

http://gstreamer.freedesktop.org/wiki/GstreamerAndroid_InstallInstructions

1)Best use NDKr6b(copy the platform[android-14])
2) ICS-src/bionic/linker/linker.c --> SO_MAX 128 --> +62 needed --> Maximum number of shared objects tat can be loaded at a time should be increased and Android Src must be recompiled
3)GST_REGISTRY_UPDATE=yes
4)GST_REGISTRY=/data/data/com.android.freedesktop.gstreamer/cache/registry.bin
5)GST_PLUGIN_PATH=/data/data/com.android.freedesktop.gstreamer/lib
6)GST_PLUGIN_SCANNER=/data/data/com.android.freedesktop.gstreamer/bin/gst-plugin-scanner
7) Better Copy the bins in the application to /system/bin/ with 777 permissions

After Building GST for ICS(android-14), I was able to play audio files on the device and also tried to ndk-build with proper JNI[Key: LDFLAGS:=-lX --> means load libX.so from LD_LIBRARY_PATH].....then I realised that there is no proper video sink for android in GST as it uses X-Overlay. so.....

https://wiki.linaro.org/WorkingGroups/Middleware/Multimedia/Specs/1105/GstreamerEglSink

Android NDK Build - Tutorial

http://marakana.com/forums/android/examples/49.html
http://earlence.blogspot.com/2009/07/writing-applications-using-android-ndk.html

Running a (*.o) Exec in Android Shell

http://jiggawatt.org/badc0de/android/

Linux Kernel Bootup Process

http://www.ibm.com/developerworks/library/l-linuxboot/index.html
http://free-7.blogspot.com/2010/10/linux-boot-process.html