Callbacks in C

A callback is any executable code that is passed as an argument to other code, which is expected to call back (execute) the argument at a given time [Source : Wiki]. In simple language, If a reference of a function is passed to another function as an argument to call it, then it will be called as a Callback function.

In C, a callback function is a function that is called through a function pointer.

Below is a simple example in C to illustrate the above definition to make it more clear:

// A simple C program to demonstrate callback
void A()
    printf("I am function A ");
// callback function
void B(void (*ptr)())
    (*ptr) (); // callback to A
int main()
    void (*ptr)() = &A;
    // calling function B and passing
    // address of the function A as argument
   return 0;

I am function A

In C++ STL, functors are also used for this purpose.

Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.

This article is attributed to GeeksforGeeks.org

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