c++/3779: Accepts illegal C++ code: redefinition of default argument
Loren James Rittle
Tue Jul 24 03:40:00 GMT 2001
>> Before reporting standard compliance issues related to
>> gcc please try compiling with -pedantic.
> As the code in question is illegal C++, I believe it at least
> should give a warning no matter which flags are used.
Perhaps illegal, but mostly harmless  (except to portability-minded
people such as us).
So that you understand the reason I gave you the answer I did, here is
the documented stance of "the collective mind of the gcc maintainers"
(from the gcc info page):
``GCC always tries to compile your program if possible; it never
gratuitously rejects a program whose meaning is clear merely because
(for instance) it fails to conform to a standard. In some cases,
however, the C and C++ standards specify that certain extensions are
forbidden, and a diagnostic _must_ be issued by a conforming
compiler. The `-pedantic' option tells GCC to issue warnings in
such cases; `-pedantic-errors' says to make them errors instead.
This does not mean that _all_ non-ANSI constructs get warnings or
There is similar section that explains why you might want to use -Wall
and/or -W with gcc since we don't like it to be noisy with warnings...
> In short: move the warning from -pedantic to all the time, and make
> it possible to force an error for this kind of illegal code.
 FYI: Since g++ currently does detect (and report by default) when
there is a mismatch between the definition and redefinition of a
default argument (i.e. a real problem), I'm not sure too many
people are going to care about this issue in practice. For your
own happiness, I think it is better for you to learn to always use
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