------- Additional Comments From tow21 at cam dot ac dot uk 2005-03-09 16:11 ------- (In reply to comment #1) > The complaint is a segfault at runtime when > you actually want to do anything with the > string whose length depends on a missing > optional argument. This isn't too bad (the > same thing happens if you access a missing > optional argument). Indeed - but even if the optional argument were present, you're still not allowed to access it in a specification expression, and this is a constraint that the compiler is required to detect at compile time. (It's a constraint that I'd quite like to see partially lifted - it would be very useful to be able to use present(arg) as part of a specification expression - but it is forbidden according to the current standard.)
-- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=20323