Nested function in C

Question

Can we have a nested function in C? What is the use of nested functions? If they exist in C does their implementation differ from compiler to compiler?

Answer 1

As others have answered, standard C does not support nested functions.

Nested functions are used in some languages to enclose multiple functions and variables into a container (the outer function) so that the individual functions (excluding the outer function) and variables are not seen from outside.

In C, this can be done by putting such functions in a separate source file. Define the main function as global and all the other functions and variables as static. Now only the main function is visible outside this module.