I compiled gmic for android, ndk, jni.
But the sample interface gmic_use_lib.cpp, for android jni interface,
I got following exception;
exception error in "/storage/sdcard0/test.bmp -cartoon 0,0,100 -output[-1] /storage/sdcard0/result.bmp " unkown command or file cartoon
which means it did't recognize the gmic command. But the same code for linux works right.

what unbelieveable thing is ,
the linux verion lib for gmic , libgmic.so ,file size is 4.9 M.
but the android version, I got a shared lib which size less than 3M

-cartoon is defined in the gmic_def.gmic file
it is not a built-in function (implemented in the .cpp)

Try to download cli_update165x.gmic and call gmic with
-m cli_update165x.gmic ...
possibly your build does not find the default gmic file!

This sounds part reasonable.
On linux platform, I could run the sample which compiled with gmic_use_lib.cpp & gmic.cpp, with libgmic.so and sample (executable file). This is ok.
The same code does't work for android.
so , I don't believe this is not a built-in function.

how to declare the compile command to build the gmic file in, and let the source code find the gmic file?

according to the docs here
http://gmic.eu/
The file "gmic_def.h" is generated from "gmic_def.gmic" (see Makefile target "def:") which ensures the standard commands compatible with that release are available.

The gmic_def.gmic convert to gmic_def.h, It has been compile into the lib? Is that wrong?

I am quite sure that gmic custom functions are not build in during compile time, even not in the library. Try to call in your build "-echo $_path_rc" to find where gmic files (and others) are expected!

thanks, you are quite a nice man.
I would tell the git page for gmic4android if I have done this