WG15 Defect Report Ref: 9945-2-54
Topic: expr

This is an approved interpretation of 9945-2:1993.


Last update: 1997-05-20



	Topic:			expr
	Relevant Sections:	4.22
	Classification:	 Ambiguous 

Defect Report:

I request an interpretation of 9945-2:1993 for section 4.22 expr.

If no operands are provided, i.e. there is no expression, then is the
expression invalid?

Some argue that no expression is tantamount to an invalid expression
(exit status 2).  Others argue that no expression falls under "an
error occurred" (exit status >2).  What is the correct interpretation
of the standard or are both interpretations correct?

[Note: I have seen both exit status 2 and 3 from different
 implementations of expr].

(Keith Stobie)

WG15 response for 9945-2:1993 
The standard is unclear on this issue, and no conformance
distinction can be made between alternative implementations
based on this. 

The standard specifies how expr should act if given one or
more operands, the standard does not address the issue when no
operands are given.

Concerns about the wording of this part of the standard have
been forwarded to the sponsor.

Rationale for Interpretation: