Is the code necessarily inserted at the call point of an inline function during compilation?

No, the compiler is not required to insert the code of an inline function directly at the call site. The inline keyword in C/C++ is merely a suggestion to the compiler, not a strict requirement. The compiler may ignore this suggestion if it considers that inlining the code would increase the binary size or degrade performance. Also, functions declared as inline should have their definitions in a header file so that the compiler can see them during compilation, but the actual inlining depends on the optimizer.