test/CodeGenCXX/extern-c.cpp

// RUN: clang-cc -emit-llvm %s -o %t &&
namespace foo {

// RUN: not grep "@a = global i32" %t &&
extern "C" int a;

// RUN: not grep "@_ZN3foo1bE = global i32" %t &&
extern int b;

// RUN: grep "@_ZN3foo1cE = global i32" %t | count 1
int c = 5;

}