Calling c function in a lib file from c++

Question

I have to call a c function declared in a lib file from c++. What instructions/attributes/configuration I have to set for this?

Why not put that as an answer instead of a comment? – OJ. Dec 01 '10 at 12:56 — OJ., Dec 01 '10 at 12:56

score 5 · Accepted Answer · answered Dec 01 '10 at 12:52

5

Do you have a header file for the library? If so it should have

extern "C" {
blah blah
}

stuff in it to allow it to be used by C programs. If not, then you can put that around the include statement for the header in your own code. E.g.

extern "C" {
    #include "imported_c_library.h"
}

answered Dec 01 '10 at 12:52

AlastairG

I don't think that will work! You need # before include, and no ; at the end. – TonyK Dec 01 '10 at 12:55
I was typing a bit too quickly. Need to re-read before hitting the button. – AlastairG Dec 01 '10 at 12:57

score 2 · Answer 2 · answered Dec 01 '10 at 12:50

2

ensure you put extern "C" before the declaration of the function if it isn't already in the header.

answered Dec 01 '10 at 12:50

CashCow

score 1 · Answer 3 · edited May 23 '17 at 12:29

1

If you're writing the header files yourself, it's often nice to do something like this

 #ifdef __cplusplus
 extern "C" {
 #endif

...

 #ifdef __cplusplus
 }
 #endif

so that this gets ignored by your c compiler, but picked up by c++ one. Incidentally, for a good discussion of why you need this, check out

edited May 23 '17 at 12:29

Community

answered Dec 02 '10 at 02:50

pythonic metaphor

3 Answers3