David Brown <da...@westcontrol.com> writes: > There is a big difference between defining an object as "const", and > merely declaring it as const or accessing it as const. When you access it > as const, you are saying "/I/ won't change the object with this access". > When you declare an object as const (such as an extern object), you are > saying "/I/ won't change this object". When you /define/ an object as > const, as you do with a "static const", you are saying "this object is > constant. It will never change value - you (the toolchain) can safely > place it in read-only memory that cannot ever change value".
You are interpreting too much into const here. The C standard says in footnote 112: "The implementation may place a const object that is not volatile in a read-only region of storage." Note the use of "not volatile". But in any case this is not part of the C standard: it's only a footnote. > And then you make it volatile, telling the compiler "this object might > change unexpectedly, or use values written to it unexpectedly". > > If someone could explain to me how this could have real-world usage, I > think it would be easier for me (and others) to be sure of what it really > means. It's an object that is never written to, but may change unexpectedly. Andreas. -- Andreas Schwab, sch...@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."
