I have been programming C++ for years, but mostly with other tools.  I
do not recall encountering this issue, e.g. with Borland's C++ Builder
or with gcc.

I was surprised today to encounter multiple symbol definitions at link
time because I happened to use <iostream> in multiple compilation
units.  I found a way to get around it, but I am not happy with it.
It seems silly to me.  I use <iosfwd> in the headers, and <iostream>
in the corresponding compilation units, to provide an overload to the
output operator for each of a number of classes; and this error
strikes.  I used the /force option for the linker, so now it compiles;
a compromise for me since I know the symbols are identical, from the
same source code, but I tend to regard all warnings as obscenities to
be purged from my code as vigorously as errors (indeed, my preference
is to pass my code through a number of tools, to take advantage of the
differing strengths of different tool chains, and mitigate their
weaknesses).

It seems odd that VC++ 2005 would have a problem with this one part of
the standard library.

Is there a way to avoid such an issue without using /force (and the
concommitant transformation of the linker error into a warning)?

Thanks

Ted