Re: [Mingw-users] linkage failure when template decls and defs are in separate files

[Robert M D. <bob...@us...>]

Greg,

Thanks for the info.  The URL is especially useful.

******************************************************************************

Bob Dorazio
United States Geological Survey
7920 NW 71 Street
Gainesville, Florida  32653
Phone:  (352) 378-8181 x373
Fax:    (352) 378-4956
Email:  bdo...@us...
Internet:  www.fcsc.usgs.gov


                                                                                                                               
                      Greg Chicares                                                                                            
                      <chicares@mindspr        To:       Robert M Dorazio <bob...@us...>,                              
                      ing.com>                  min...@li...                                              
                                               cc:                                                                             
                      01/15/2003 01:28         Subject:  Re: [Mingw-users] linkage failure when template decls and defs are in 
                      PM                        separate files                                                                 
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Robert M Dorazio wrote:
>
> I'd like to keep template declarations and template definitions in
separate
> files; however, I encounter the following error when trying to compile
and
> link a simple example (taken from p. 351, Stroustrup 2000 The C++
> Programming Language).
[...]
> export template<class T_numtype> void out(const T_numtype& t) {
  ^^^^^^

gcc doesn't support 'export', and neither do most
compilers. AFAIK only comeau does.

This URL discusses gcc template options:
  http://gcc.gnu.org/onlinedocs/gcc/Template-Instantiation.html
Don't try the -frepo thing; it doesn't work with
mingw, because it requires collect2, which mingw
does not supply. Before trying any -f... options,
look them up in the manual for the version of gcc
you're using, because some of them may have been
removed or deprecated.

You can do explicit instantiation, declaring every
template in a header and implementing it in a .cpp
file. I've done it but it didn't seem to have any
real effect on compile times--so conceivably I
overlooked something. But since that experiment
I've just put template implementations in headers.