Issue 0134: Is error number an undefined term?

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

Authors: Clive Feather, Project Editor (P.J. Plauger)
Date: 1994-01-31
Submitted against: C90
Status: Closed
Converted from: dr.htm, dr_134.html

Subclause 7.11.6.2 The strerror function, page 168, reads:

The strerror function maps the error number in errnum to an error message string.

However, “error number” is an undefined term. Must strerror provide a valid message for every value of type int, or can some values be a domain error, allowing it to return garbage or a null pointer? If the latter, then what are the values that must generate a valid string? Must the following generate a valid string:

zero

EDOM and ERANGE

the value of any other symbol defined in <errno.h>

any value that a library routine might set errno to

Comment from WG14 on 1997-09-23:

Response

The strerror function must provide a valid message for the error numbers EDOM, ERANGE, and any other value a library function might store in errno. For all other values, the behavior is undefined.