The correct solution

Since #include is a simple text replacement by the preprocessor, we can put the extern "C" declaration in our C++ code, where it belongs:

//main.cpp

extern "C" {
#include "foo.h"
}

int main() {
foo(22);
}

This way, everything inside the header, including the indirectly included declarations in other C headers, appear inside the extern "C" declaration.

Approach 3: Synbol Tables

Built-in function locals() and globals() return a dictionary of current local and global symbol table respectively. So you could call a function just like:

def my_func(arg1, arg2):
print(arg1, arg2)
return arg1 + arg2

r = locals()['my_func'](http://1, 2)
print(r)

The output is:

1 2
3

This approach is just like the examples provided in the very beginning of this post, in which, I maintained a symbol table by myself and called the function by its string-typed name.