The explanation in 13.4.3 [temp.arg.nontype] paragraph 2 of why a string literal cannot be used as a template argument leaves something to be desired:
...because a string literal is an object with internal linkage.I can't find anything that says that a string literal has internal linkage. In fact, I'd be pretty surprised if I did, since linkage is defined (in 6.6 [basic.link] ) strictly in terms of names, and a string literal doesn't have a name. Actually, I think that it's the namelessness of a string literal that prevents it from being a template argument; only the third and fourth bullets of 13.4.3 [temp.arg.nontype] paragraph 1 could conceivably apply, and both of those require that the entity have a name (i.e., that they be given as an id-expression).
Proposed Resolution (10/99): In 13.4.3 [temp.arg.nontype] paragraph 2, change
[Note: a string literal (5.13.5 [lex.string] ) is not an acceptable template-argument because a string literal is an object with internal linkage.to
[Note: a string literal (5.13.5 [lex.string] ) does not satisfy the requirements of any of these categories and thus is not an acceptable template-argument.