[boost] Re: [dynamic_bitset] Stream extraction failures on CodeWarrior 9.4

10 May 2005

      On May 10, 2005, at 5:41 AM, Gennaro Prota wrote:
...
--- Doug Gregor <dgregor@cs.indiana.edu> wrote:
...
The stream extraction operators for dynamic_bitset are failing on
CodeWarrior 9.4. See: http://tinyurl.com/addko
Is anyone familiar enough with the quirks of Metrowerks' iostreams to
fix this issue?
Hi Doug, Jeremy and Howard
unfortunately, due to a series of vicissitudes that would be too long 
to tell,
I have no home connection at the moment (a situation that lasts from 
several
months) and thus I can't work on CVS. Howard Hinnant is probably the 
person who
knows Metrowerks compiler and library best. Howard?
This is preliminary, but I'm currently thinking this is compiler error. 
  The following local array:

   std::string strings[] = {
                   // NOTE: "const" gives the usual problems with Borland
                   //       (in Tests::stream_extractor instantiation)

#if !(defined __BORLANDC__     \
       && BOOST_WORKAROUND(BOOST_RWSTD_VER, BOOST_TESTED_AT(0x20101)))
                                         // Borland 5.5.1 with RW 
library crashes
             // empty string
             std::string(""),
             // no bitset
             spaces,
#endif
             // no bitset
             std::string("x"),
             std::string("\t  xyz"),

             // bitset of size 1
             std::string("0"),
             std::string("1"),

             std::string("  0  "),
             std::string("  1  "),
             spaces + "1",
             "1" + spaces,
             spaces + "1" + spaces,
             std::string("  x1x  "),
             std::string("  1x  "),

             // long bitset
             long_string,
             "  " + long_string + " xyz",
             spaces + long_string,
             spaces + long_string + spaces
     };

in run_test_cases() appears to get destructed right after it is 
constructed.  I haven't figured out what the trigger is yet.  I haven't 
been able to reproduce the symptom in a smaller example, and it doesn't 
appear to happen with the other strings[] local array:

     std::string strings[] =     {
                                   std::string(""),
                                   std::string("0"),
                                   std::string("1"),
                                   std::string("11100"),
                                   get_long_string()
                                 };

Destruction of "short" strings is harmless as we're using the short 
string optimization.  But once you hit strings[13] (corresponding to 
the long_string entry) then the test starts working with a string with 
entries other than '0' and '1', and things pretty much fall apart.

A workaround is to declare the strings[] array static.

I've sent a test case to the compiler team and if they turn up any 
further information or workarounds I'll pass it on here.

-Howard