Android Shell undefined reference to `_hxcpp_argc'

[mgood7123]

this is requires to pass command-line arguments to Haxe for it to return via Sys.args()

extern int _hxcpp_argc;
extern char **_hxcpp_argv;

extern "C" void hxcpp_main();

int main(int argc, char *argv[]) {
	_hxcpp_argc = argc;
	_hxcpp_argv = argv;
	hxcpp_main();
	return 0;
}

hxcpp/src/hx/StdLibs.cpp

Line 55 in 75b25c3

int _hxcpp_argc = 0;

hxcpp/src/hx/StdLibs.cpp

Line 56 in 75b25c3

char **_hxcpp_argv = 0;

exec("haxe -cp src --main src.Main -cpp cpp_build-android " + LIBS + " -D HXCPP_ARM64 -D android -D PLATFORM=android-9 -D ANDROID_NDK_ROOT=\"" + NDK + "\"")

exec(NDK + "/toolchains/llvm/prebuilt/windows-x86_64/bin/clang++.exe -Wl,-rpath,. --target=aarch64-linux-android21 main.cpp liblog.so libandroid.so libEGL.so libGLESv2.so libGLESv1_CM.so libOpenSLES.so liblime.so cpp_build-android/libMain-64.so")

C:\Users\small\AppData\Local\Temp\main-d0f624.o: In function `main':
main.cpp:(.text+0x10): undefined reference to `_hxcpp_argc'
main.cpp:(.text+0x14): undefined reference to `_hxcpp_argc'
main.cpp:(.text+0x18): undefined reference to `_hxcpp_argv'
main.cpp:(.text+0x1c): undefined reference to `_hxcpp_argv'

[Aurel300]

What is the issue? Is the first snippet a suggested fix or…?

[mgood7123]

the issue is _hxcpp_argc is undefined

the first snippet is what produces undefined reference to `_hxcpp_argc'

[tobil4sk]

The linking error happens because _hxcpp_argc is not exported publicly by the libMain-64.so, so when main.cpp is linked against it, there is no public _hxcpp_argc symbol that it can find.

I think the proper approach if you want to have a int main(int argc, char* argv[]) definition is to rely on this:

hxcpp/include/hx/HxcppMain.h

Line 9 in 9d6db96

#elif defined(HX_ANDROID) && !defined(HXCPP_EXE_LINK)

When building with -D exe_link, hxcpp will fall back to a standard main entry point instead of the usual java one.However, the exe linker has not been implemented for modern clang-based toolchains. Perhaps this can be done.

However, android apps usually don't get invoked from this standard entry point, this only happens for programs invoked via a developer shell, so I'm not sure it would make sense for a lime app.

[tobil4sk]

With #1383, this now works:

class Main {
  static function main() {
    trace("hello world");
    trace(Sys.args());
  }
}

$ haxe -m Main --cpp bin -D android -D exe_link
# ...
$ adb push bin/Main-64 /data/local/tmp/
# ...
$ adb shell "/data/local/tmp/Main-64 hello world"
Main.hx:3: hello world
Main.hx:4: [hello,world]