Ting 이네 Software 이야기

Here is the way to compile x86 goldfish and run on emulator

* AOSP Marshmallow + Goldfish 3.4

* ARCH=x86 (You don't need to set SUBARCH)

* Compiler version : gcc-4.8 (prebuilt x86 compiler from Android NDK)

  (Set CROSS_COMPILE environment variable)

$ make ARCH=x86 CC="${CROSS_COMPILE}gcc -mno-android" goldfish_defconfig

$ make ARCH=x86 CC="${CROSS_COMPILE}gcc -mno-android" -j40

And use 'arch/x86/boot/bzImage' as 'kernel-qemu' image

StackOverlow 의 아래 답변을 참고하자.

http://stackoverflow.com/questions/2213340/what-is-daemon-thread-in-java

정리하면, JVM은 main thread가 끝나더라도, 아직 수행중인 다른 thread - non daemon thread(user thread) - 가 있다면, 중지되지 않는다.

즉, process가 계속해서 돈다.

C/C++ 처럼, main thread가 exit될 때 process를 종료시키려면, 모든 child thread 속성을 daemon thread로 설정해야 한다.

Thread t = new Thread(...)

t.setDaemon(true);

남아 있는 모든 thread가 Daemon thread일 경우, JVM은 중지된다.

다만, 이런식으로 thread가 급작스레 종료하는 것은 상당히 불안정한 결과를 가져 올 수 있으므로 주의해야 한다.

다시 말하면, 단 하나라도 종료되지 않은 user thread (non-daemon thread) 가 존재할 경우, JVM은 종료되지 않고, 모든 다른 thread (Daemon thraed 포함)역시 계속해도 수행된다.

In general, main function is used as below.

But, it can be expanded like below

By this way, we can use environment variables easily.

=> This matches parameters of execle() and execvpe() at Linux.

GNUMake document says

"An argument that contains ‘=’ specifies the value of a variable: ‘v=x’ sets the value of the variable v to x. If you specify a value in this way, all ordinary assignments of the same variable in the makefile are ignored; we say they have been overridden by the command line argument"

This means, value defined as command-line argument has top priority in terms of variable definition.

< Make file >

PRIV_V=hello_OUT

$(info $(PRIV_V))

all: a b

@echo all

a: PRIV_V := hello_A

a:

@echo $(PRIV_V)

b: PRIV_V := hello_B

b:

@echo $(PRIV_V)

< Test >

$ export PRIV_V=ENV

$ make

hello_OUT

hello_A

hello_B

all

$ make PRIV_V=CMD

CMD

CMD

CMD

all

* Tips : Variable definition in gnumake command line.

Variable definition syntax in the Makefile, is also available as command line argument.

Example.

$ make CC=Hello

$ make CC:=Hello

$ make CC+=Hello