Re: Question about leading underscores

From: rwgk_at_[hidden]
Date: 2001-06-24 10:42:40

--- In boost_at_y..., "Corwin Joy" <cjoy_at_h...> wrote:
> Fair enough.  But I claim you are still not technically safe if you 
prefix
> with an underscore, because, as specified in the standard 
17.4.3.1.2, "Each
> name that begins with an underscore is reserved to the 
implementation for
> use as a name in the global namespace".  [note that this says 
nothing about
> whether the underscore is followed by an uppercase letter].

I am the original poster who started this thread. My question
was motivated by a problem with the following piece of code:

struct IspaceData {
  std::map<Miller::Index, int, Miller::hashCompare> IndexDict;
  sgtbx::SgOps _sgops;

  IspaceData(sgtbx::SgOps& s):_sgops(s){}
};

With the Compaq Tru64 version 6.2 cxx compiler, this eventually
results in unresolved symbols. If "_sgops" is replaced by something
that does not start with an underscore, compiling and linking
succeeds.

In view of the messages in this thread, and in view of our
own experience, wouldn't it be better to strictly avoid the use
of leading underscores in the boost library? It is a very low
price to pay, compared to the trouble one has to go through
if some unfortunate compiler's use of identifiers conflicts
with that of the library.

Thanks!
        Ralf