Function pointers

[Subha Ramanathan]

Sir/Mam,
I am a beginner in C language ,Can you say me what is the difference between an ordinary function and a function pointer.How function pointer is advantageous over normal functions.

Thanks
Subha

[Banfa]

Well I function is a function.

A function pointer is not a function at all, it is a variable containing the location of a function.


Function pointers are useful when you wish to be able to pass a function to another piece of code so that it can call the function provided. A general example of this is callback functions, you call a function with some data including a pointer to a function. Under certain circumstances the called function then calls the function you have provided a pointer to.

A specific example of this is qsort. qsort sorts any array given the number of elements and the size of the elements in the array and a pointer to a comparison function.