I think gcc behaves correctly. The non-0x pair has a two-argument constructor taking const references to T1 and T2 (20.2.2p2). Therefore the 0 you pass is directly regarded be the null pointer constant. The 0x pair has a 1...N argument _template_ constructor (20.2.2p6 of the current draft). The 0 is regarded to be an int, and therefore you are passing an actual int to initialize a pointer. std::pair<int, int*> x(0,nullptr); or std::pair<int, int*> x(0,static_cast<void*>(0)); should work fine though. -Christopher Beman Dawes schrieb:
On Thu, Sep 3, 2009 at 11:27 AM, Beman Dawes<bdawes@acm.org> wrote:
Thanks to Noel Belcourt, the trunk Sandia-gcc tests show results side-by-side for gcc 4.4.1 without and with C++0x features enabled.
See http://beta.boost.org/development/tests/trunk/developer/summary.html
Several Boost libraries are passing without 4.4.1 C++0x features but failing with them:
http://beta.boost.org/development/tests/trunk/developer/assign.html ...
I missed iostreams. The problem seems to be a bug in gcc. This program:
#include <utility>
int main() { std::pair<int, int*> x(0,0); return 0; }
compiles without -std=gnu++0x, but with -std=gnu++0x gets an error:
c:\gcc\bin\../lib/gcc/i386-pc-mingw32/4.4.0/../../../../include/c++/4.4.0/bits/stl_pair.h: In constr uctor 'std::pair<_T1, _T2>::pair(_U1&&, _U2&&) [with _U1 = int, _U2 = int, _T1 = int, _T2 = int*]': cvt-0-to-ptr.cpp:5: instantiated from here c:\gcc\bin\../lib/gcc/i386-pc-mingw32/4.4.0/../../../../include/c++/4.4.0/bits/stl_pair.h:90: error: invalid conversion from 'int' to 'int*'
I tried to find this in gcc bugzilla, but didn't come up with anything. Is anyone else have any knowledge of this problem?
--Beman _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost