Is there a way to define C inline function in .c file rather than .h file?

Question

As I know, C inline function body should be defined in .h file because it causes an error 'function-name used but never defined" if body defined in .c file.

Is this the regular way? Or how to define inline function body in .c file?

Answer 1

Each .c file is compiled independently into .o output. If you define the inline function in a .c file, other source files cannot see such function, so that cannot be inlined.

Therefore the inline function should be in the .h file to allow the code to be shared.