[Mingw-users] What does linkage directive actually do?

[Southp <is...@ci...>]

Recently, I come into a problem caused by the linkage directive :extern "C".

As far as I know, we need to apply this directive when we attempt to use
functions written in C.

However, I wonder how the compiler distinguishes a function written in C or
C++?

 

The situation I encountered is, I compiled a program, which included
functions written in C, with GCC and VC .NET.

With .NET, application of linkage directive is necessary. However, I had to
remove it or had a linkage error replied by GCC.

 

I'm so confused. When should I use linkage directive? How does compiler (VC
.NET or GCC.especially GCC) distinguish functions written in C or C++?

 

Any help is appreciated, thanks!