C: What is wrapper function and how it is written in C language ?

Question

Which is the best practice for variable declaration within the function ? Or is it vary from one language to other one ?

Answer 1

Wrapper function gives you flexibility add extra functionality before or after execution of actual function.
Using macro it is written

define WRAPPER(fun, arg1, arg2) \

{\
ret = fun(arg1, arg2);\
return (ret); \
}

In case later on if prototype is changed for fun, it starts taking three arguments you have to change this MACRO definition.
In all places where it is called you don't need to change.

define WRAPPER(fun, arg1, arg2) \

{\
int arg3;\
ret = fun(arg1, arg2, arg3);\
return (ret); \
}

For end user it is still same number of arguments that need to be passed through WRAPPER.