On 1/26/19 3:37 PM, Martin Jambor wrote:
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" ...?
Would this work?
-Wabsolute-value warns for calls to standard functions that compute
the absolute value of an argument when a more appropriate standard
function is available. For example, calling abs(3.14) triggers
the warning because the appropriate function to call to compute
the absolute value of a double argument is fabs. The option also
triggers warnings when the argument in a call to such a function
has an unsigned type.
Martin
