String literal allowed in integral constant expression?
7.7 [expr.const]
Martin v. Loewis

Created on 2002-07-29.00:00:00 last changed 161 months ago


Date: 2003-10-15.00:00:00

[Voted into WP at October 2003 meeting.]

Date: 2002-10-15.00:00:00

Proposed resolution (October 2002):

Change the beginning of the second sentence of 7.7 [expr.const] paragraph 1 which currently reads

An integral constant-expression can involve only literals (5.13 [lex.literal]), ...
to say
An integral constant-expression can involve only literals of arithmetic types (5.13 [lex.literal], 6.8.2 [basic.fundamental]), ...

Date: 2002-07-29.00:00:00

According to 15.2 [cpp.cond] paragraph 1, the if-group

#if "Hello, world"

is well-formed, since it is an integral constant expression. Since that may not be obvious, here is why:

7.7 [expr.const] paragraph 1 says that an integral constant expression may involve literals (5.13 [lex.literal]); "Hello, world" is a literal. It restricts operators to not use certain type conversions; this expression does not use type conversions. It further disallows functions, class objects, pointers, ... - this expression is none of those, since it is an array.

However, 15.2 [cpp.cond] paragraph 6 does not explain what to do with this if-group, since the expression evaluates neither to false(zero) nor true(non-zero).

Date User Action Args
2008-10-05 00:00:00adminsetstatus: wp -> cd1
2004-04-09 00:00:00adminsetmessages: + msg1008
2003-11-15 00:00:00adminsetstatus: ready -> wp
2003-04-25 00:00:00adminsetstatus: review -> ready
2002-11-08 00:00:00adminsetmessages: + msg734
2002-11-08 00:00:00adminsetstatus: open -> review
2002-07-29 00:00:00admincreate