Help: Call a function

Discussion in 'C' started by maabm78, Mar 5, 2010.

  1. maabm78

    maabm78 New Member

    Joined:
    Mar 5, 2010
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    0
    Dear All;

    Please could anyone help me. How can I call a function in C file from C++ file?
    Please it is urgent.

    Best regards
     
  2. shabbir

    shabbir Administrator Staff Member

    Joined:
    Jul 12, 2004
    Messages:
    15,345
    Likes Received:
    382
    Trophy Points:
    83
    Include the header file and call as a normal function.
     
  3. maabm78

    maabm78 New Member

    Joined:
    Mar 5, 2010
    Messages:
    2
    Likes Received:
    0
    Trophy Points:
    0
    I did that, but I got "[Linker error] undefined reference to `function_name'".
    I used Dev-C++ compiler.

    I did a simple code.
    Code:
    /*
    * add.h
    */
    #ifndef ADD1_H
    #define ADD1_H
    
    int addnum(int a, int b);
    
    
    #endif
    Code:
    /*
    * add.c
    */
    #include "add.h"
    
    int addnum(int a, int b)
    {
    return a+b;
    }
    
    Code:
    /*
    * main.cpp
    */
    #include <stdio.h>
    #include "add.h"
    
    int main (void) {
    int i,j,z;
    i=4;
    j=5;
    z = addnum(i,j);
    printf("%d\n", z);
    return 0;
    }
     
  4. techgeek.in

    techgeek.in New Member

    Joined:
    Dec 20, 2009
    Messages:
    572
    Likes Received:
    19
    Trophy Points:
    0
    Occupation:
    EOC (exploitation of computers)..i m a Terminator.
    Location:
    Not an alien!! for sure
    Home Page:
    http://www.techgeek.in
  5. Abinila

    Abinila New Member

    Joined:
    Feb 20, 2010
    Messages:
    8
    Likes Received:
    0
    Trophy Points:
    0
    Try this,

    Add the following line in your add.h file. Like,

    Code:
    
    #ifndef ADD1_H
    #define ADD1_H
    #include "add.c"
    
    int addnum(int a, int b);
    #endif
    


    Other wise,



    If you have an individual C function that you want to call, and for some reason you don't have or don't want to #include a C header file in which that function is declared, you can declare the individual C function in your C++ code using the extern "C" syntax. You need to use the full function prototype:

    Code:
    
       extern "C" void f(int i, char c, );
     extern "C" {
       void   f(int i, char c);
       int    g(char* s, char* s2);
    }
    
    Call the function like,

    Code:
    int main()
     {
       f(10, 'x');    
     }
    
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice