Shriramana Sharma wrote: > > If a programmer has chosen to pass a reference rather than a value, > > even if no reference is actually required, intentions to improve > > run-time performance come into mind. It is much more intuitive to > > pass primitives by value and use references only where appropriate, > > since performance gains due to the use of the const qualifier are very > > small and negligible in most cases. > > I am somewhat confused. As I see it, the usage of a const ref for > passing a parameter by reference is to improve runtime performance, yes, > but it is not through the "const" part of it. It is through the > reference part of it, which avoids a copy of the parameter being > constructed which can be costly with large classes or structs. The const > part of it is only there to prevent the function from modifying the > source data, whether intentionally or accidentally. There may be a > side-effect of optimization, but at least to my understanding the intent > of const here is making the source read-only. Is this understanding wrong? The const is primarily for correctness (ensuring that the callee doesn't modify the data), but there may also be a performance gain. -- Glynn Clements <glynn@xxxxxxxxxxxxxxxxxx> - To unsubscribe from this list: send the line "unsubscribe linux-c-programming" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
