How to prevent functions be inlined while building as .cpp ?

I am currently using Unity 2017.2.f1. When I build my project in iOS, the App size is about 101M, so I have to do something to reduce the size.

My unity project will generate .cpp code by using il2cpp scripting backend. It seems that all functions will be inlined. So I want to trying removing all inline keywords.

Is there any good ideal about that?

This is generally pretty difficult to do, and often not the best idea. In our experience the decisions which the C++ compiler makes for inlining are often pretty good performance vs. size trade-off. Even using C++ compiler directives to indicate that you don’t want a some code inlined only give hints to the compiler.

You will probably have better luck with build size looking elsewhere, like assets in the project or removal of unused managed code.