Re: Potentially "dangerous" changeset, please test

[Michael Goffioul]

2011/10/7 Michael Goffioul <address@hidden>:
> 2011/10/6 Jordi Gutiérrez Hermoso <address@hidden>:
>> 2011/10/6 Michael Goffioul <address@hidden>:
>>
>>> As I suspected, the change above fails to compile under MSVC, because
>>> the header to include is <unordered_map>, not <tr1/unordered_map>.
>>> In C++11, the header to include is also <unordered_map>. So I suggest
>>> you write a configure test to check for the header location and namespace
>>> to use.
>>
>> If you know how to do this, could you please do it yourself? If not,
>> please wait until I figure out how. :-)
>
> For the namespace detection, you could try (disclaimer: completely untested):
>
> unordered_map_requires_tr1_namespace=no
> if test "$ac_cv_header_unordered_map" = "yes; then
>  AC_COMPILE_IFELSE([
>    AC_LANG_PROGRAM([
>      #include <unordered_map>
>    ], [
>      std::unordered_map m;
>    ]),
>  [unordered_map_requires_tr1_namespace=yes])
> fi
> if test "$unordered_map_requires_tr1_namespace" = "yes"; then
>  AC_DEFINE(USE_UNORDERED_MAP_WITH_TR1, 1, [Defines whether
> unordered_map requires the use of tr1 namespace.])
> fi
>
> Then in rand.cc, you could then use:
>
> #if USE_UNORDERED_MAP_WITH_TR1
> using namespace std::tr1;
> #else
> using namespace std;
> #endif
>
> And then you can simply use unordered_map in the rest of the code.

Note that you may also need to surround these snippets with
AC_LANG_PUSH(C++) and AC_LANG_POP(C++). As well as with
AC_MSG_CHECKING([whether unordered_map requires tr1 namespace])
and AC_MSG_RESULT([$unordered_map_requires_tr1_namespace])

Michael.