From: bangerth Date: Thu, 23 Aug 2007 14:46:21 +0000 (+0000) Subject: Remove the entry on gcc 2.96. We haven't heard any reports about this compiler out... X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f96de3e79ebab0646f197125d20db3bb43550ad8;p=dealii-svn.git Remove the entry on gcc 2.96. We haven't heard any reports about this compiler out in the wild for quite a while. git-svn-id: https://svn.dealii.org/trunk@15026 0785d39b-7218-0410-832d-ea1e28bc413d --- diff --git a/deal.II/doc/faq.html b/deal.II/doc/faq.html index 33b95522c6..8f466a9d26 100644 --- a/deal.II/doc/faq.html +++ b/deal.II/doc/faq.html @@ -5,7 +5,7 @@ The deal.II FAQ - + @@ -27,8 +27,6 @@
  • I tried to install deal.II on system X and it does not work.
  • How do I change the compiler? -
  • I cannot compile deal.II - with gcc version 2.96!
  • I cannot link with BLAS or LAPACK even if the libraries exist
  • Can I use deal.II on a @@ -80,88 +78,6 @@

    -     -

    I cannot compile deal.II - with gcc version 2.96!

    - -

    - You can't, this version of gcc simply does not work with - deal.II, or at least did not. deal.II - version 4.0 will contain fixes to allow compilation, but versions - up to and including 3.4 cannot be compiled with gcc 2.96. Furthermore, later - versions don't support this compiler any more at all, and will tell you so - during configuration. -

    - -

    - gcc 2.96 was created by - RedHat from a snapshot somewhere between 2.95 and 3.0; it contained a large - number of compiler bugs, which have partly been fixed, but too many remain as - that we were able to make the library work with this compiler until we could - get hold of such a system (initially, the main development of - deal.II was done in Germany, which is SuSE country, not - Red Hat). Also note that version 2.96 is not an officially - released version of gcc. Simply use either gcc 2.95 or 3.X. The reason we - finally decided not to support this compiler is that we - have reports that gcc 2.96 may miscompile parts of the library, see for - example - this - message. We have also found that some of the example programs return - wrong values or go into infinite loops if compiled with this version of gcc. -

    - -

    - RedHat provides updates to gcc version 3.0 or later, and downgrades - to gcc version 2.95, all of which work with deal.II. Red - Hat releases starting with version 8.0 will also be based on a different - compiler, so the problem does not exist there any more. -

    - -

    - However, there are more problems lurking around the corner: even though we - have included patches so that the library can be compiled, presently not all - of the examples can. There is at least one problem in the compiler which we - could not work around (I reported this to the gcc bug tracking system as - c++/616 in October 2000, and it was fixed a few weeks later, but apparently - did not make it to Red Hat's version). The problem manifests itself in - situations like this: -

    - 
    -    template <int dim> struct Function {};
-    template <int dim> struct RHS : Function<dim> { RHS() {}; };
-
-    template <int dim> void f ()
-    {
-      const RHS<dim> rhs;
-    };
-    template void f<1> ();
-
    - -

    Here, the compiler reports

    - 
    -    x.cc: In function `void f () [with int dim = 1]':
-    x.cc:7:   instantiated from here
-    x.cc:5: uninitialized const `rhs'
-
    -

    - which is clearly bogus since rhs uses the default constructor of - the class. Unfortunately, there is no way of working around the bug short of - removing the constness of the variable. We did not want to do this, since - this changes the semantics of the programs and is promoting bad style which - we do not want to do in example programs. Furthermore, since gcc 2.96 is - being phased out at the time of this writing, there is no point in doing this - any more. Therefore, we advise you to remove the constness of these variables - if you are forced to use this compiler and want to use the example programs, - or use them as the basis for your own - project. You can either do this by hand, or by using - this - patch that is archived in out mailing list - archives. A better way is probably to up- or downgrade your compiler, if - this is possible for your machine. -

    - -

    I cannot link with BLAS or LAPACK even if the libraries exist