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

From:

Juha Nieminen <nospam@thanks.invalid>

Newsgroups:

comp.lang.c++

Date:

03 Apr 2012 14:09:09 GMT

Message-ID:

<4f7b0485$0$4369$7b1e8fa0@news.nbl.fi>

Qi <no@no.com> wrote:

A compiler should be smart enough to not give a warning in the above
case even if NDEBUG is defined (because, after all, the variable *is*
used: As a parameter to a macro.)

When compiler sees the code, that line has gone if NDEBUG is defined
because it's removed by preprocessor if assert is empty when NDEBUG
is defined.
So there is still warning, no?

  In the era where the C preprocessor, the compiler and the linker were
all completely separate programs that might have been the case (because
the compiler, which is the one issuing warnings, does not see the original
source code, only the code generated by the C preprocessor).

  However, in modern compilers there really is no need to separate the
C preprocessor from the compiler so at least in principle the compiler
could see that "hey, this variable is given as parameter to this macro"
and thus elide the warning.

  OTOH, I don't know if any modern compiler is that smart... I'm just
talking hypothetically here.