Re: libstdc++/5801: valarray doesn't work as expected with complex types

[Gabriel Dos Reis <gdr@codesourcery.com>]

The following reply was made to PR libstdc++/5801; it has been noted by GNATS.

From: Gabriel Dos Reis <gdr@codesourcery.com>
To: Andre.dos.Anjos@cern.ch
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: libstdc++/5801: valarray doesn't work as expected with complex types
Date: 08 Apr 2002 13:45:49 +0200

 Andre.dos.Anjos@cern.ch writes:
 
 [...]
 
 | The following code compiles cleanly, but crashes
 | ****
 | #include <valarray>
 | 
 | typedef std::valarray<int> vint;
 | 
 | int main (void)
 | {
 | 	vint sample(3, 10); //a sample
 
 OK.
 
 | 	std::valarray<vint> x(sample,4); //four of the sample
 
 This is not OK (but I made it work):  std::valarray<T> works only with
 some restrictions on T.  T must be "friendly", that is there should be
 no semantic difference between
 
    T u(t);
 
 and
   
    T u;
    u = t;
 
 assuming t is of type T.
 
 a std::valarray<T> does not obey the abbove rule so you can't say
 std::valarray<std::valarray<T> > and expect a reasonable behaviour.
 
 | 	std::valarray<bool> mask(true, x.size());
 | 	mask[1] = false;
 | 	std::valarray<vint> y(x[mask]); ///< crashes
 
 This is not permitted -- and I didn't have a time to make it work.
 
 -- Gaby