I'm trying to use gmic's filter in android. I compile it on ubuntu , ndk, gmic version:1.6.2.0
errors:
/gmic.cpp:1976:23: error: 'l' was not declared in this scope
cimg_forY(selection,l) if (selection[l]==ind) return true;
gmic.cpp:1990:23: error: 'cimg' has not been declared
std::FILE *file = cimg::fopen(filename,"r");
.... many others.
Is it portable to android?

Maybe not, but there is a web based version of g'mic that you can try to run on your android.

https://gmicol.greyc.fr/

you mean gmic is not portable on android ?
I believe that gmic could run on android...the question I meet, must be some dependence lib which missing.
online gmic is hard to use, it depends on good network

Your error above doesn't look like an error due to the Android port. It looks like a syntax error but if we assume that this code compiles correctly somewhere else, this could be due to slight differences in C++ standards used. You may have to try some compiler options to make it check for a specific level of the standard.

On the other hand, Android is for machines with a small CPU, not really the kind of machines to run heavy image processing. Your app may win the "fastest battery drain" contest.

I looked into the detail of that question. It's something related with compiler, of course due to android(not pure linux).
but portable to android makes sense.