int buf_print ( struct buf * buf ); int buf_compare ( struct buf * a , struct buf * b ); // ... // 在C++代码中 extern "C" { #include "buf.h" class BufInCPP : public buf { BufInCPP (): data(0), len(0) {} int print () { return buf_print( this ); } int compare () { return buf_compare( this ); }

typedef int (*fn)(int);
extern "C" void caller(fn);
extern "C" int my_fn(int);
// ...
caller(my_fn); // 编译错误