On Fri, 7 Nov 2008 15:28:40 -0700 chromatic <[EMAIL PROTECTED]> wrote: > On Friday 22 June 2007 02:07:32 Nicholas Clark wrote: > > I think that you need something like this > > > > /* concatenating with "" ensures that only literal strings are > > accepted as argument */ #define STR_WITH_LEN(s) (s ""), > > (sizeof(s)-1) > > > > /* STR_WITH_LEN() shortcuts */ > > #define newSVpvs(str) Perl_newSVpvn(aTHX_ STR_WITH_LEN(str)) > > I'm not sure that's what I was asking. > > string_from_cstring()'s third parameter can be either the length of > the string or zero. If it's zero, the function will call strlen() to > get the string's length. > > If we're passing in a string literal, it seems silly to pass in a > length of 0, as we're recalculating a constant on every call. I > don't see that this macro fixes that.
It uses sizeof, not strlen. So, it pushes the calculation to compile-time, so you only have to do it once, and never at runtime. Also, using sizeof() will fix some cases that strlen() doesn't handle correctly, specifically, strings containing explicit null characters. src/objects.c has a few examples of that. string_to_cstring(interp, "\0", 0) will get the size wrong, but string_to_cstring_literal(interp, "\0") will get it right. So I don't really see a good excuse for not using it everywhere. > I do agree that updating strings and string lengths can be tedious, > but I'm not aware of any C89-compliant solution to keep the two > synchronized. sizeof() isn't C89? Mark
