What does mean for a name or type to have a certain language linkage?

Question

According to (c) ANSI ISO/IEC 14882:2003, page 127:

Linkage specifications nest. When linkage specifications nest, the innermost one determines the langu

Answer 1

"the name f2 has C++ language linkage" In C++ language linkage not only the name of the function defines it but also the type of it arguments and the return value. in this case you have: void f2(void); but you can define with it: void f2(int a); without conflict because the linkage will see them as different types, a thing you wouldn't be able to do in C language.

"the function's type has C language linkage" I don't know the details but I know the high level of it. Basically it makes a C++ compiled function linkable from C. If I remember correctly In C and in C++ the way the parameters are passed to a function is different. In this case the function f2 will pass the parameters as C compiler does this. this way the function will be linkable both from C and C++.