[Bf-committers] problems with C++

Jonathan Merritt j.merritt at pgrad.unimelb.edu.au
Tue Oct 4 08:29:28 CEST 2005

Nathan Letwory wrote:

>With only template class SpTemp<int> it works for msvc too, but adding
>template class SpTemp<double> makes it choke on it. (Yes, I added the
>extra line also to where the <int> is). Additionally, it is not really
>helpful to use such a class if you have to declare *every* templated usage
>in the implementation files, thus kinda defeating the purpose of templated

Hmm... it's a bit odd that it should work for one case but not two.  I'm 
running Linux only though, so I can't test with anything more than gcc.

I agree that having to declare every template usage does make things 
more difficult, but it doesn't completely defeat the purpose of 
templates; afterall, you don't have to re-specify the *entire* class, 
under some different name, for each combination of types, you just add a 
single line to achieve that effect.  In most scenarios I've seen, a 
final source tree will only use very limited number of combinations of 
template parameters.  If the number is excessive, you could even 
generate them using a script to produce all the required combinations.

Obviously, it's far far less useful for a library of templated classes! :-)

Let's see whether the C++ experts have any suggestions.  This was only 
one idea; something I've used in the past (on my own internal, gcc-only 
projects) to avoid having enormous header files included with each *.cpp 


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