Defect Report #004

Submission Date: 10 Dec 92
Submittor: WG14
Source: X3J11/90-012 (Paul Eggert)
Question 1
Are multiple definitions of unused identifiers with external linkage permitted?
The wording in subclause 6.7 permits multiple definitions of identifiers with external linkage, so long as the identifiers are never used. For example, the following program is ``strictly conforming'' if you read the wording in subclause 6.7 literally:
int F() {return 0;}
int F() {return 1;}
int V = 0;
int V = 1;
int main() {return 0;}
This must be a bug in the wording of subclause 6.7. It cannot have been the Committee's intent, since it prohibits the most commonly encountered linker model. For example, most linkers will flatly refuse to link the following ``strictly conforming'' program
int F() {return 0;}
int G(int i) {return i;}
int F() {return 1;}
int G(int);
int main() {return G(0);}
because F is defined twice.
This Defect Report referred to an earlier draft of the C Standard, and was corrected prior to the publication of the C Standard.
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