Undefined reference for a C++ function when called from C function

Question

I am trying to call a C++ function from a C function and i see a undefined reference to a function written .cc file, Below is the code. What am i missing?

externcpp.cc

#include <iostream>
 #include "example.h"
 using namespace std;
 int main ()
 {
    cout << "I am " << __func__ << "In File " << __FILE__;
    return 0;
 }
 void example_fun()
 {
    cout << "I am" << __func__ << "in File __FILE__";
 }

externc.c

#include <stdio.h>
#include "example.h"
int test1()
{
    printf(" I am [%s] and from File [%s]\n",__func__,__FILE__);
    printf("Calling C++ Function from C\n");
    example_fun();
    return 0;
}

example.h

#ifndef EXAMPLE_H
#define EXAMPLE_H

#ifdef __cpluscplus
#define EXTERNC extern "C"
#else
#define EXTERNC
#endif

EXTERNC void example_fun();
#endif

And used following commands for compilation and linking

g++ -c -o externcpp.o externcpp.cc -Wall
gcc -c -o externc.o externc.c -Wall
g++ -o output externcpp.o externc.o

Regards,

Why is there a trailing { on your #define EXTERNC? It seems to never be closed. — John Zwinck
– John Zwinck, Commented Jan 8, 2015 at 6:59
externc.o: In function 'test1' externc.c: (.text+0x2d) : undefined reference to 'example_fun' collect2: error: ld returned 1 exit status — user3631987
– user3631987, Commented Jan 8, 2015 at 7:03

AnT stands with Russia · Accepted Answer · 2015-01-08 07:05:20Z

9

It's supposed to be #ifdef __cplusplus, not #ifdef __cpluscplus as in your code above. Check your spelling.

answered Jan 8, 2015 at 7:05

AnT stands with Russia

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2 Comments

Ulrich Eckhardt Over a year ago

Ew, those are errors you can stare at for hours without seeing them. Good catch!

user3631987 Over a year ago

Yes that was the error after making that change i got the required result thanks to all. Thanks @AndreyT

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