Callback function , what is it

[sapman]

In the name of God.

I know the function pointers .

Please Describe the Callback functions and using them in C++ .

Please Give me an Example ( Don't use Sorting functions , they are confusing me..);

Thanks in advance.

[ventsyv]

Call back function is exactly what the name suggests a function that you "call back" after you've done your work. Think of it as passing a function pointer that you have to execute after the initial function has finished executing. Example:

Code: Select all


//Call
myFunction(status, HandleResultFunction);

//
myFunction(int, SomeFuncPointer)
{
   //Do work.

   //work is done send the result to a function that will handle it
   SomeFuncPointer
}


It's used in multi-threading application, it doesn't make much sense in single thread apps. MyFunction might contain a loop that runs every 5 seconds, so it never returns to the caller, but it's "sending" the results it generated to another function that process them (and is running in another thread).