Why can't I specify the storage class for formal parameters of a function?

Question

When I do as below the code works fine :

#include 
void test( int a)
{
 printf(\"a=%d\\n\",a);   
}

int main()
{
    test(10);
    return 1;
}
         


        

Answer 1

First,quoting C11, chapter 6.7.6.3

The only storage-class specifier that shall occur in a parameter declaration is register.

So, this is explicitly specified in the standard.

That said, this restriction exists because with an explicit storage class like static/ extern, there will be problems in memory management, as function parameters are in the block scope for the function and their lifetimes are limited to the execution of the function body.

• A parameter variable cannot outlive the call to the function; otherwise, what would be the effect of the argument in the next call to the same function? So static storage is not meaningful, and auto is redundant.

• Since the function parameters has no linkage, extern also makes no sense.

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Additionally, as mentioned in C11, for a hosted environment, the conforming signature for main() is int main(void), at least.