Re: [boost] RC_1_30_0 compile error with SGI MIPSpro Compilers

From: Ralf W. Grosse-Kunstleve (rwgk_at_[hidden])
Date: 2003-03-05 17:14:05

Below is a stand-alone minimal test that still produces the same error message
with MIPSpro:

% CC -LANG:std zminmin.cpp
cc-1108 CC: ERROR File = zminmin.cpp, Line = 13
  The indicated expression must have pointer-to-function type.

      static const unsigned long value = sizeof(bdhelper_t::check());
                                                ^

1 error detected in the compilation of "zminmin.cpp".

The same code works correctly with gcc 2.96 and an EDG245-based compiler
(Compaq cxx). However, here is an interesting observation:

% cxx -std strict_ansi zminmin.cpp
% a.out
4

No problem with "strict_ansi." But:

% cxx -std ansi -D__USE_STD_IOSTREAM zminmin.cpp
cxx: Error: zminmin.cpp, line 13: operand of sizeof may not be a function
    static const unsigned long value = sizeof(bdhelper_t::check());
----------------------------------------------^
cxx: Info: 1 error detected in the compilation of "zminmin.cpp".

I am jumping to the conclusion that older EDG's don't support
sizeof(some_function()). Does that sound plausible? What could be done to make
the is_base_and_derived test work with MIPSpro?
Is the test actually used in Boost.Python? -- I noticed that MIPSpro chokes
even if is_base_and_derived_impl2 is not instantiated.

Thanks!
        Ralf

#include <iostream>

template <typename B, typename D>
struct bd_helper
{
  static int check();
};

template<typename B, typename D>
struct is_base_and_derived_impl2
{
    typedef bd_helper<B,D> bdhelper_t;
    static const unsigned long value = sizeof(bdhelper_t::check());
};

int main()
{
  unsigned long n = is_base_and_derived_impl2<int, float>::value;
  std::cout << n << std::endl;
}

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