Submitter: Project Editor (Larry Jones)
Submission Date: 2006-06-03
Source: <whyglinux@gmail.com>
Reference Document: N/A
Version: 1.2
Date: 2007-10-10
Subject: String literals in compound literal
initialization
Summary
6.5.2.5 Compound literals, paragraph 3 in ISO/IEC 9899:1999 C Standard says:If the compound literal occurs outside the body of a function, the initializer list shall consist of constant expressions.This is to say a string literal, which is neither a constant nor a constant expression, can not be taken to initialize a compound literal with static storage duration. However, this is not the fact.
String literals can not be constants because they are not among constants (defined in Section 6.4.4). When a string literal is used to initialize a compound literal (in the case an array type), the array-to-pointer conversion does not occur (6.3.2.1 Lvalues, arrays, and function designators, paragraph 3), and hence the string literal can not be an address constant, which is the only chance to become a constant expression.
Obviously string literals should be mentioned together with constant expressions. It should be:
If the compound literal occurs outside the body of a function, the initializer list shall consist of constant expressions or string literals.
The following paragraph excerpted from Page 125, 6.7.8-4 seems to support the above correction:
All the expressions in an initializer for an object that has static storage duration shall be constant expressions or string literals.
Suggested Technical Corrigendum
Change 6.5.2.5, paragraph 3, to:
If the compound literal occurs outside the body of a function, the initializer list shall consist of constant expressions or string literals.
Proposed Technical Corrigendum
Replace 6.5.2.5 paragraph 2 and 3 to:
All the constraints for initializer lists in 6.7.8 are applicable to compound literals.
Change 6.5.2.5 paragraph 7 to:
All the semantic rules for initializers lists in 6.7.8 are applicable to compound literals.82)