extern "C"

lackluster · 07-24-2002, 12:52 PM

what does this do? i always see it in headers but don't understand...

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

Mara · 07-24-2002, 03:02 PM

Code between #ifdef __cplusplus and #endif (of course, the right #endif) is included when the header is included to a C++ file. It allows to have one header for C and C++.

tyler_durden · 07-24-2002, 11:36 PM

its needed so you can call a c function from cpp

lackluster · 07-25-2002, 12:09 PM

Quote:

Code between #ifdef __cplusplus and #endif (of course, the right #endif) is included when the header is included to a C++ file. It allows to have one header for C and C++.

I assumed that, but why does there need to be extern "C" { } in a cpp header?

Quote:

its needed so you can call a c function from cpp

So C & C++ have different calling conventions??

Mara · 07-25-2002, 12:19 PM

Well, such ticks are needed, because C code will work in C++ program, but it won't the other way.
Note that the code you've found is the first part. There's also second one (because '{' needs a '}') at teh end.