Re: Need your experience: is "(void)param;" to avoid unused variable warnings well known for you?

Victor Bazarov <v.bazarov@comcast.invalid>
Mon, 02 Apr 2012 09:49:07 -0400
On 4/2/2012 7:39 AM, Fred Zwarts (KVI) wrote:

"Qi" wrote in message news:jlc1qv$kjj$

Hi all,

Let me show some code first,

void someFunction(int param)
(void)param; // param is not used in this function. This line is
// just to silence the compiler warning about unused param.

Please note the "(void)param".
Is that usage common or well known for you?
Or you rarely saw it? Or even it's weird to you?

Just your experience is enough, no need to debate for it's good
or bad. :-)

The reason I ask this is, in my another thread, some very veteran
C++ developers said they rarely saw that kind of usage.
That makes me a little nervous because I used it a lot in my
code to *improve* the code readability.
If it's not well known trick then it reduces code readability
and then I'm going to change my code about that.

That's not only about coding style but also about code readability.

Looking forward to hearing your experience.


I have never seen this trick. Why don't you use the standard C++ way?
Remove the name of the parameter and the compiler will stop complaining.
Less code, better readability. The "(void)param" makes me wonder what
the purpose is. You will need comments to explain why it is used. If the
parameter name is omitted, it is immediately clear that it is not used
in the function. No comments needed. For the reason why it is not used
in the function, comments may be needed in both cases.

void someFunction(int)


I've seen that trick usually used in (a) a larger function than just one
empty line and one line of comment, and (b) in presence of some reason
to keep the argument name, like alternative configurations
(Debug/Release for instance):

    void someFunction(int argumentUsedOnlyInDebug)
        ... // some code
    #ifdef NDEBUG
        ... // some code that uses argumentUsedOnlyInDebug
        ... // more code

Any suggestions for a better alternative?

I do not respond to top-posted replies, please don't ask

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