Re: [Groff] compiler errors troff 1.19

[Werner LEMBERG]

[Antoine, I'm CCing to you in the hope that you know the C++ standard
 as well as C.]

> I'm trying to compile groff on Solaris 8 with
> Sun WorkShop 6 2000/06/19 C 5.1 Patch 109491-02. Unfortunately it seems
> to have problems with the code:
> 

> CC -I. -I/home/elkner/tmp/build/groff-1.19/src/roff/troff
>    -I/home/elkner/tmp/build/groff-1.19/src/include
>    -I/home/elkner/tmp/build/groff-1.19/src/include -DHAVE_CONFIG_H
>    -xtarget=ultra -xarch=v8plus -xO3 -c div.cpp
>
> "env.h", line 313: Error: Multiple declaration for title_length.
> "env.h", line 314: Error: Multiple declaration for space_size.
> ...

Hmm, in class `environment' defined in env.h we first have

  hunits title_length;

declaring a variable.  Later then we have (in the same class)

  friend void title_length();

to make the function `title_length()' (defined in another file env.cc)
to be a friend function of this class.

It seems that your C++ compiler (contrary to any other I'm aware of)
just looks at the symbol `title_length', ignoring the scope (declaring
a function as `friend' which is in the same class is useless AFAIK).
I'm not sure whether this is a compiler bug or whether this is
undefined behaviour in the C++ standard.  Or is this new C++
behaviour?  The `natural' way to access a top-level definition could
be

  friend void ::title_length();

but this gives a compilation error with my gcc.  Saying

  friend void std::title_length();

works for me (and probably for you too), but I'm pretty sure that this
fails with older C++ compilers which don't support namespaces;
additionally I believe that this is the wrong approach.


    Werner