[Bug c++/12222] explicit initialization of static template members seems ignored

[bangerth at dealii dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12222


bangerth at dealii dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-09-09 14:08:31
               date|                            |


------- Additional Comments From bangerth at dealii dot org  2003-09-09 14:08 -------
Your code is invalid: you have the explicit instantiation before the declaration 
of an explicit specialization of the member. That confuses the compiler. If you 
revert the order, you get this error message: 
 
tmp/g> ../build-gcc/gcc-install/bin/c++ x.cc -W -Wall 
/tmp/ccQIMlpO.o(.text+0x11): In function `main': 
: undefined reference to `a<float>::b1' 
collect2: ld returned 1 exit status 
 
That is due to the fact that you only _declare_ the existence of an explicit specialization, 
not define it. If instead of 
  template <> b a<float>::b1; 
you write 
  template <> b a<float>::b1 = b(); 
then the code compiles properly and yields the expected result. 
 
Now, this is indeed confusing -- gcc should be able to issue a warning about specializing 
after instantiating. Besides, there is kind of a bug anyway: when accessing  
a<float>::b1.m, gcc is apparently presently using the static member from the general 
template, not the specialization. That's fine, because the code is invalid. However, it 
is equally apparently not initializing it properly, since otherwise we would get the 
right answer. 
 
W.