Hello Michael,
first of all: Thanks for the fast reply!
On Thu Oct 06, 2005 10:33, you wrote:
>> [..]
>>
>> It's a feature. It is undefined behavior to have conflicting declarations
>> in different translation units.
>> [...]
Well, but shouldn't there at least be a warning during linking!?
>> [..]
>> In that case, how does VC++ implement cout,cin,.... construction?
>> In libstdc++ (well, at least in gcc-3.4) it is implemented by doing
>> something like:
>>
>> namespace std{
>> ...
>>
>> // Note that this is different from <iostream>'s definition of cin
>> // (it's declared as "extern istream cin" in there).
>> char cin[ sizeof(istream) ];
>> ...
>> ios::Init::Init()
>> {
>> if (count++ == 0)
>> new (&cin) istream(cin_constuction_flags);
>> ....
>> }
I don't know how VC++ implements cout, cin. I just checked the symbol names
with the dumpbin.exe tool that is part of the VC++ Suite and there it is
clearly marked as "maximum (int)". And during the attempt to link you get a
unresolved symbol error saying that main.o needs "maximum (double)" but lib
only offers "maximum (int)" and that's very helpful. I encountered this
behaviour on Linux because of a very strange SEGV and I was finally able to
track that down to an extern variable that was used in the wrong way and thus
I found the mentioned behaviour. I did not take a look at the VC++ libc
implementation etc. I just checked it from the user perspective.
Thanks,
WR
