Using a C library.

I have a library of functions written in C; specialMaths.a and it’s header specialMaths.h

The specialMaths.a has been compiled for Android and IOS.

How do I call these functions from my program?

Do I need to make a plugin? or is there an easier way?

You need to make that into a plugin or use the native build process.

Which is easier?

I tried the basic example, which has App and Plugin, it built, but I don’t see an .apk or java library or anything.

Is there a simple step-by-step tutorial to make a plugin for Android and IOS?

According to this it looks kind of easy https://docs.coronalabs.com/native/plugin/index.html#native-c

But how exactly? I guess I have to compile and link that - against what? where do I get the libraries and the headers? And what do I do with the .a or .so file?

Doing the native build is easier and will get you to your goal more quickly.

I can’t help you with the how.  Just keep pluging away reading the docs.

You need to make that into a plugin or use the native build process.

Which is easier?

I tried the basic example, which has App and Plugin, it built, but I don’t see an .apk or java library or anything.

Is there a simple step-by-step tutorial to make a plugin for Android and IOS?

According to this it looks kind of easy https://docs.coronalabs.com/native/plugin/index.html#native-c

But how exactly? I guess I have to compile and link that - against what? where do I get the libraries and the headers? And what do I do with the .a or .so file?

Doing the native build is easier and will get you to your goal more quickly.

I can’t help you with the how.  Just keep pluging away reading the docs.