c - 函数指针 : why is (*fptr)(6, 7) 与 (fptr)(6,7) 相同，如果函数是 add(int , int )

Question

在 function pointers ,

为什么是(*fptr)(int a, int b)与 (fptr)(int a, int b) 相同函数指针是否赋值给add函数？

int (*fptr)(int ,int) = add; 
while add(int a , int b) returns sum of two numbers.    

Answer 1

说明

C 没有函数对象，因此取消引用函数指针是没有意义的。因此，当函数指针被取消引用时，它(有一些异常(exception))立即变回函数指针。

引用文献

n1570 (当前C标准的最终公开草案):

6.5.3.2 Address and indirection operators

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

...

6.3.2.1 Lvalues, arrays, and function designators

4. A function designator is an expression that has function type. Except when it is the operand of the sizeof operator, the _Alignof 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’’.