Question

I can’t think of any practical use of multiple asterisks in the function call:

void foo(int a, char b)
{

}

int main(void)
{
    (**************foo)(45, 'c');

    //or with pointer to function:
    void (*ptr)(int, char) = foo;
    (******ptr)(32, 'a');
}

Why is this thing allowed both in C and C++?

Answer 1

Why is this thing allowed both in C and C++?

I can’t speak for C++, but for C at least a function designator is converted to a pointer:

6.3.2.1 – 4

A function designator is an expression that has function type. Except
when it is the operand of the sizeof operator or the unary & operator,
a function designator with type ‘‘function returning type’’ is
converted to an expression that has type ‘‘pointer to function
returning type’’.

Applying the indirection operator yields a function designator:

6.5.3.2 – 3

The unary * operator denotes indirection. If the operand points to a
function, the result is a function designator

So no matter how many times you apply the indirection operator you’ll get the same thing: a function designator that’s immediately converted to a pointer.

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In my opinion there’s little or no use in doing this.