[Mingw-users] Re: EXAMPLE OF std::auto_ptr errors with MINGW, seems ok to MS Visual C++

[Brian D. <sea...@ho...>]

Greg Chicares <chi...@mi...> wrote:

 > Try posting a minimal self-contained example that
 > we can compile.

Ok!  Here's a "test.cpp"...

1: #include <memory>
2:
3: class BASE { int i; };
4:
5: class DERIVED : public BASE { int j; };
6:
7:  void DoSomething(std::auto_ptr<BASE> pbase) { }
8:
9:  int main()
10:     {
11:     std::auto_ptr<DERIVED> pderived (new DERIVED);
12:     DoSomething(pderived);
13:     }

When I run gcc "test.cpp", this gets compiler errors:

   test.cpp: In function `int main()':
   test.cpp:12: no matching function for call to
   `std::auto_ptr<BASE>::auto_ptr(std::auto_ptr<BASE>)'

   D:/DEV/MINGW/include/c++/3.2/memory:346: candidates are:
   std::auto_ptr<_Tp>::auto_ptr(std::auto_ptr_ref<_Tp>)
   [with _Tp = BASE]

   D:/DEV/MINGW/include/c++/3.2/memory:216:
   std::auto_ptr<_Tp>::auto_ptr(std::auto_ptr<_Tp1>&)
   [with _Tp1 = BASE, _Tp = BASE]

   D:/DEV/MINGW/include/c++/3.2/memory:203:
   std::auto_ptr<_Tp>::auto_ptr(std::auto_ptr<_Tp>&)
   [with _Tp = BASE]

   test.cpp:12: initializing temporary from result of
   `std::auto_ptr<_Tp>::operator std::auto_ptr<_Tp1>()
   [with _Tp1 = BASE, _Tp = DERIVED]'

If I change the code to read:

9:  int main()
10:     {
11:     std::auto_ptr<BASE> pderived (new DERIVED);
12:     DoSomething(pderived);
13:     }

Then the compilation proceeds without these complaints.  I do get some 
strange new errors regarding new/delete I don't recall having using the old 
gcc, though...

   C:\DOCUME~1\Brian\LOCALS~1\Temp/ccI1aaaa.o(.text+0x2e):test.cpp:
   undefined reference to `operator new(unsigned)'

   C:\DOCUME~1\Brian\LOCALS~1\Temp/ccI1aaaa.o 
(.text$_ZNSt8auto_ptrI4BASEED1Ev+0xf):test.cpp:
   undefined reference to `operator delete(void*)'

   C:\DOCUME~1\Brian\LOCALS~1\Temp/ccI1aaaa.o(.eh_frame+0x12):test.cpp:
   undefined reference to `__gxx_personality_v0'

Make sense?  Can anyone fix one (or, hey, both!) of these problems?  ;)

Thanks much!

---
Brian Dickens
http://phred.org/~brian

_________________________________________________________________
Unlimited Internet access for only $21.95/month.  Try MSN! 
http://resourcecenter.msn.com/access/plans/2monthsfree.asp