"John Maddock" <john@johnmaddock.co.uk> wrote on 10/26/2007 03:28:05 AM:
Joel,
Fusion's tuple tests are passing with IBM xlc, but the TR1 tuple tests are failing with problems with std::pair, which in turn causes all the Boost.Math tests to fail: it appears that just including the header ../boost/fusion/adapted/std_pair.hpp is enough to trigger the issue :-(
See http://tinyurl.com/3cfz2n for a typical error message.
Is this fixable, or should I degrade TR1 to the old tuples implementation
for this compiler? BTW the old spirit-fusion code did work with xlc I believe.
Chris: the code that's failing looks so innocuous it's hard to see how it
could fail: there's nothing odd in xlc's headers like an extra defaulted template argument for std::pair is there?
Thanks, John Maddock.
I believe I have a fix for this in the compiler. I ran a large batch of tests last night but have not checked the results, however the smoke tests I did run seemed ok. This compiler change will likely take some time to make it into a production driver (on the order of a month or two if I can sneak it in). The problem with boost::fusion:traits::tag_of<>, and make_vector<> is that we are not considering default arguments for partial specializations. The code sequence is a forward declaration using default arguments followed by a partial specialization definition. Our compiler explicitly disallowed the checking of default arguments for partial specilizations. Most likely this was just an oversight on our part, but I will need to clarify with the standard. Here is a small test-case that causes the error message as well show the problem: //Begin t.C template <typename T0 = void, typename T1 = void> struct make_vector; template <typename T0> struct make_vector<T0> { }; //End t.C The workaround in the Boost source code would be to specify the default argument explicitly. I tried the following change for boost/fusion/adapter/std_pair.hpp and the error message disappeared. --- boost/fusion/adapted/std_pair.hpp.orig 2007-10-26 11:31:11.276781194 -0400 +++ boost/fusion/adapted/std_pair.hpp 2007-10-26 11:31:32.676781424 -0400 @@ -20,7 +20,7 @@ namespace traits { template <typename T1, typename T2> - struct tag_of<std::pair<T1, T2> > + struct tag_of<std::pair<T1, T2>, void > { typedef struct_tag type; } Not an ideal fix, but illustrates where the change for our compiler is necessary in the Boost source. The changes would need to be made in fusion/adapter/std_pair.hpp, fusion/sequence/generation/make_vector.hpp, fusion/sequence/generation/make_list.hpp to name a few :-( So there is a source work around as well as a compiler fix. Like I mentioned earlier it will be some time before the compiler change is reflected into a production compiler. One of our internal requirements that we have for publishing results is that the compiler used to publish results has to be available to customers therefore I cannot use a pre-release compiler for nightly Boost runs. How would you like to proceed? Chris Cambly XL C++ Compiler Development