Solved

Declaring external functions within a class

Posted on 2003-12-01
2
199 Views
Last Modified: 2010-04-01

I've created a Dynamic Link Library in C++ (Borland C++ Builder to be exact).
The DLL contains one class (in this case we'll call it class1) which has both public and private functions.

Is it possible to implement some of the "class1" functions outside of  the class1.cpp file?
i.e. implement functions func1 and func2 below in a separate .cpp file?

header file definition for class1:
~~~~~~~~~~~~~~~~~~~

    class  __EXPORT_TYPE class1 {
    public:
        char * func1 (char * aParam1);
        char * func2 (char * aParam2);
        char * func3 (char * aParam3);
    private:
        char * func3 (char * aParam4);
        char * func4 (char * aParam5);
   }

As there is around 100 functions to implement, it would nice to implement these in different .cpp files.
I've tried to declare them as "extern" in the class1 definition although the compiler does not seem to like this.

hope you can help.


Cheers,

weslondon

0
Comment
Question by:weslondon
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 11

Accepted Solution

by:
bcladd earned 400 total points
ID: 9850953
You have already separated the header from the implementation file, right? All you need to do is write the appropriate implementation files and tell the compiler they are all required for the object to be built. This is a dependency/linking problem rather than a C++ problem:

(1) There is no need to extern the functions because they are not external IF you link all of the .cpp implementation files into the DLL

(2) The declaration of the functions is already separate from the definitions so no client of class1 needs to care about how you structured your source code.

Hope this helps,
-bcl
0
 
LVL 86

Expert Comment

by:jkr
ID: 9851107
bcladd is right - no need to specify them as "extern". You basically would

------------->8-------------------------------

// header.h

   class  __EXPORT_TYPE class1 {
   public:
       char * func1 (char * aParam1);
       char * func2 (char * aParam2);
       char * func3 (char * aParam3);
   private:
       char * func4 (char * aParam4);
       char * func5 (char * aParam5);
  };


------------->8-------------------------------

// functions1.cpp
#include "header.h"

char * class1::func1 (char * aParam1) {
}

char * class1::func2 (char * aParam1) {
}

------------->8-------------------------------

// functions2.cpp
#include "header.h"

char * class1::func3 (char * aParam1) {
}

------------->8-------------------------------

// functions3.cpp
#include "header.h"

char * class1::func4 (char * aParam1) {
}

char * class1::func5 (char * aParam1) {
}


0

Featured Post

Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Often, when implementing a feature, you won't know how certain events should be handled at the point where they occur and you'd rather defer to the user of your function or class. For example, a XML parser will extract a tag from the source code, wh…
IntroductionThis article is the second in a three part article series on the Visual Studio 2008 Debugger.  It provides tips in setting and using breakpoints. If not familiar with this debugger, you can find a basic introduction in the EE article loc…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The viewer will learn how to clear a vector as well as how to detect empty vectors in C++.

733 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question