Hi, On Sat, Jan 26 2019, Gerald Pfeifer wrote: > On Sat, 26 Jan 2019, Martin Jambor wrote: >> I'd like to propose the following hunk mentioning -Wabsolute-value in >> changes.html of the upcoming gcc 9. Is it OK? > > Lovely^WThanks, ok! > > Actually, one question: > >> + <li><code>-Wabsolute-value</code> warns when a wrong absolute value >> + function seems to be used or when it does not have any effect because >> + its argument is an unsigned type. The <code>-Wabsolute-value</code> >> + option is included in <code>-Wextra</code>. > > What is a "wrong absolute value function"? That might be good to > show by means of an example? (Also in invoke.texi, which I checked > before writing this.)
Most usually wrong means an absolute value function for a shorter type than the one privided, such as abs when labs would be approproiate, or abs or labs when you actually need llabs. Or using normal floating-point absolute value function such as fabs for binary-coded-decimal. Or even for a complex double/float, which hitherto passed without a warning. I'm not sure how to change the wording, perhaps "...when a used absolute value function seems wrong for the type of its argument" ...? Martin
