Computer C++ inline function module

Hi All programmers/reviewers,

I hope you would be aware of inline functions in C++. Here I will not discuss about "what is inline" and explain it, rather I would tell few important (in-line) about inline functions.

For information about inline functions, you can get the data using the links like
1) http://www.parashift.com/c++-faq-lite/inline-functions.html
2) http://www.codersource.net/cpp_tutorial_inline_functions.html
3) Inline or NOT to inline in C++ http://www.thescripts.com/forum/thread59977.html
4) Wikipedia http://en.wikipedia.org/wiki/Inline_function

Let's take an example
//Declaration for C++ Tutorial inline sample:
inline int add(int x,int y);


If you are working on the code, you would have find that in most of the code, the inline function defintion is in the header file with declaration

//Definition for C++ Tutorial inline sample:
inline int add(int x,int y)
{
return x+y;
}


Why is it so ??
Let's take a simple example that the definition and declaration does not lie in the same file. Declaration lies in header file math.h and Definition lies in source file math.cpp

Let's go in the important property of inline functions.

It replaces the function called with the function contents inside the module. Here there is one condition attached that the inline function would work only in the same module e.g. if you have a module Mathematics which declares and defines the inline function add(int, int) and you have a different module called as Physics (has some file as phy.cpp) which calls the inline function as
s = add (a,b);
then the compiler (especially in Linux) is going to throw the reference error .. YES !! The reason is that the compiler is unable to open the function becasue the function is defined as inline in the other module.

How to Solve such issues ?

There are two ways to get the solution

1) Make the function as NOT inline. i.e. make the function as

int add(int x,int y) in declaration and define it in definition.

2) Declare and Define the function as inline in the header file itself. and then include this header file wherever the function add(int,int) is being called. This will ensure that the function add is also expanded as inline :)

So phy.cpp would be containing the line #include "math.h"


Enjoy !!
Adhir