Question

Imagine a function signature that accepts int or unsigned int or any POD.
Is there any benefits to const them if you are just reading from them>?

The only one I can think of, is so that you don’t mess up and assign to it accidentally?

Answer 1

I am assuming that you are talking about the top-level qualifier as in void f( const type x ), rather than the const of the pointed/referred object. In that case, it is important to note that the language determines that the top level const-volatile qualifier in function arguments is removed from the signature of the function, that is, the following declare the same function:

void f( int );
void f( const int );
void f( volatile int );
void f( const volatile int );

From that point of view, in the declaration there is no point in adding cv-qualifiers. Now in the definition the cv-qualifiers are actually checked by the compiler, and in that case it will flag changes to the arguments as errors. I have seen some people suggesting you should and some suggesting you should not use const in the definitions to catch mistakes, but in most code I have seen, const was not used.