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Re: Wuninitializable-member (PR7651 Define -Wextra strictly in terms of other warning flags)


On 29 Dec 2006 20:46:11 +0100, Gabriel Dos Reis
<gdr@integrable-solutions.net> wrote:
"Manuel LÃpez-IbÃÃez" <lopezibanez@gmail.com> writes:

| :ADDPATCH c++:
|
| This patch continues the effort to fix PR7651 [1].
|
| A new option -Wuninitializable-member [*] takes over the warning for a
| non-static reference or non-static const member appearing in a class
| without constructor. The new option is enabled by -Wextra, so we keep
| the current behaviour but add the ability to enable/disable this
| individual warning.

Why -Wuninitializable-member?

I would think that -Wuninitialized should take over this.


My primary reason was to not break current behaviour: adding this warning to -Wuninitialized will move the warning from Wextra to Wall (since Wuninitialized is enabled by Wall).

Now, there are other reasons, which may or may not be relevant:

1) -Wuninitialized only works when using optimisation, while this
warning does not have such requirement;

2) the description of Wuninitialized (Warn if an automatic variable is
used without first being initialized or if a variable may be clobbered
by a setjmp call) does not clearly match the purpose of this C++
warning;

3) it is well-known that Wuninitialized could be improved [*] and that
many users specifically disable Wuninitialized because it emits too
many false positives. However, no false positive seems to be possible
for this warning, and as you said, it is a warning that many users
that disable Wuninitialized may like to use.

Another alternative could be to rename this warning as
Wmissing-constructor and it could also include another Wextra warning:
"A base class is not initialized in a derived class' copy
constructor".

Thoughts anyone?

Cheers,

Manuel.


[*] http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

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