Callback function in C

Nitya Raut

Answered on 9th Apr, 2019

The callback is basically any executable code that is passed as an argument to other code, that is expected to call back or execute the argument at a given time. We can define it in other words like this: If the reference of a function is passed to another function argument for calling, then it is called the callback function.

In C we have to use the function pointer to call the callback function. The following code is showing how the callback function is doing its task.

Example Code

#include<stdio.h>
void my_function() {
   printf("This is a normal function.");
}
void my_callback_function(void (*ptr)()) {
   printf("This is callback function.\n");
   (*ptr)();    //calling the callback function
}
main() {
   void (*ptr)() = &my_function;
   my_callback_function(ptr);
}

Output

This is callback function.
This is a normal function.