使用C中的空参数列表访问传递给函数的参数

Question

Since functions with empty parameter lists can be passed a variable number of parameters in C, Suppose I have a function defined as :

void foo(){
// I want to access the parameters passed in here
}

And I call it with arguments, say

foo(1,2,3);

Is it possible for me to get a hold of the values of those passed arguments inside my foo() function? I'm hoping for something along the lines of $_ , the default variable in Perl.

EDIT: The kind of behavior im expecting is like the one depicted in this question : C function with no parameters behavior

Answer 1

C99:

6.5.2.2 Function calls

[...]

6. If the expression that denotes the called function has a type that does not include a prototype, the integer promotions are performed on each argument, and arguments that have type float are promoted to double . These are called the default argument promotions . If the number of arguments does not equal the number of parameters, the behavior is undefined.

(Emphasis mine.)

Thus foo(1,2,3) has undefined behavior. It's not guaranteed to even enter the function body, let alone give you access to extra arguments.

Answer 2

undefined behavior
Maybe you need Variadic Arguments