Issue 0242: Make the base standard and Annex F consistent for logb(0)

This issue has been automatically converted from the original issue lists and some formatting may not have been preserved.

Authors: Fred Tydeman (US)
Date: 2001-02-25
Reference document: ISO/IEC WG14 N943
Submitted against: C99
Status: Fixed
Fixed in: C99 TC2
Converted from: summary-c99.htm, dr_242.htm

Summary

logb(0) should be considered a pole error in the base standard (it already is in Annex F).

Details

logb(0) is inconsistent between 7.12.6.11 (domain error) and Annex F (range error via divide-by-zero).

logb(0) is effectively the same as log(0), log2(0), or log10(0), all of which are a pole or singularity error, which is a divide-by-zero exception to Annex F and a range error to 7.12. But, logb treats it as a domain error in 7.12.6.11.

Suggested Technical Corrigendum

In 7.12.6.11 logb:

Change:

A domain error may occur if the argument is zero.

to

A range error may occur if the argument is zero.

Comment from WG14 on 2001-10-16:

Technical Corrigendum

In 7.12.6.11 logb:

Change:

A domain error may occur if the argument is zero.

to

A domain error or range error may occur if the argument is zero.