Re: pkg/32670: multimedia/vlc (in pkgsrc-2005Q4) does not compile [with fix]

[Rhialto <rhialto%falu.nl@localhost>]

The following reply was made to PR pkg/32670; it has been noted by GNATS.

From: Rhialto <rhialto%falu.nl@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: pkg-manager%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        pkgsrc-bugs%netbsd.org@localhost, rhialto%falu.nl@localhost, 
joerg%britannica.bec.de@localhost
Subject: Re: pkg/32670: multimedia/vlc (in pkgsrc-2005Q4) does not compile 
[with fix]
Date: Mon, 30 Jan 2006 23:07:07 +0100

 On Mon 30 Jan 2006 at 20:30:02 +0000, joerg%britannica.bec.de@localhost wrote:
 >  This patches are incorrect or rather the use is absolutely correct.
 
 Maybe the use is correct - yet it does not compile.
 
 From comp.std.c I have learned that NULL should always be cast to the
 correct type. In C++ where more type conversions are made this seems
 even more important.
 
 >  Please check your build environment where the incorrect (C-style void *)
 >  declaration of NULL comes from.
 
 My build environment is a plain 3.0/amd64 into a chroot made with
 pkg_comp.  Of course I have my preferences in /etc/mk.conf but none that
 would influence NULL, I'd say (and if they did I would call it a bug).
 
 I recall another package that needed similar fixes before, also due to
 wxWidgets, but I don't remember which it was (maybe it was even vlc).
 
 I don't think a C-style (void *) version of NULL is the problem, since the
 compiler complains about ambiguous overloading, and the arguments it
 can't decide between are const wxString* and long int. That could happen
 only if NULL is 0, not if it is (void *)0. (Aside: even in C NULL should
 not be defined as (void *)0 since it that is a data pointer, and those
 cannot be converted to a function pointer, i.e. (void (*)())NULL would
 fail to compile).
 
 Looking at the error message which prints "NULL" explicitly it would
 even seem that it doesn't matter - that g++ is painfully aware of the
 NULLness of the pointer.
 
 With some trouble I got the pre-processed text (g++ -E -dD -C) and this
 is how it defines NULL:
 
 # 1 "/usr/include/sys/null.h" 1 3 4
 /*      $NetBSD: null.h,v 1.6 2003/10/24 21:45:09 enami Exp $   */ 
 # 11 "/usr/include/sys/null.h" 3 4
 #define NULL __null 
 
 I expect that this definition can hardly be improved. From the errors, I
 conclude that __null behaves as plain 0.
 
 pkg_comp:default.conf# gcc -v
 Using built-in specs.
 Configured with: 
/home/nick/work/netbsd/src/tools/gcc/../../gnu/dist/gcc/configure 
--enable-long-long --disable-multilib --enable-threads --disable-symvers 
--build=i386-unknown-netbsdelf2.0. --host=x86_64--netbsd --target=x86_64--netbsd
 Thread model: posix
 gcc version 3.3.3 (NetBSD nb3 20040520)
 
 These are the errors (there are lots of warnings too):
 
 if c++ -DHAVE_CONFIG_H -I. -I. -I../../..   -I/usr/pkg/include -I/usr/include 
-D
 GLX_GLXEXT_LEGACY -I/usr/pkg/include/freetype2 -I/usr/X11R6/include 
-DSYS_NETBSD
  -I../../../include `top_builddir="../../.." ../../../vlc-config --cxxflags 
plug
 in wxwindows` -Wsign-compare -Wsign-compare -Wall -O2 -I/usr/pkg/include 
-I/usr/
 include -DGLX_GLXEXT_LEGACY -I/usr/pkg/include/freetype2 -I/usr/X11R6/include 
-p
 thread -finline-limit-30000 -pipe -MT libwxwindows_plugin_a-open.o -MD -MP -MF 
"
 .deps/libwxwindows_plugin_a-open.Tpo" \
   -c -o libwxwindows_plugin_a-open.o `test -f 'open.cpp' || echo 
'./'`open.cpp; 
 \
 then mv -f ".deps/libwxwindows_plugin_a-open.Tpo" 
".deps/libwxwindows_plugin_a-o
 pen.Po"; \
 else rm -f ".deps/libwxwindows_plugin_a-open.Tpo"; exit 1; \
 fi
 
 ...
 
 open.cpp: In constructor `wxvlc::OpenDialog::OpenDialog(intf_thread_t*,
    wxWindow*, int, int, int)':
 open.cpp:385: error: call of overloaded `wxComboBox(wxPanel*&, <anonymous
    enum>, const char[1], wxPoint, wxSize, int, NULL)' is ambiguous
 
/pkg_comp/obj/pkgsrc/multimedia/vlc/default/.buildlink/include/wx-2.6/wx/gtk/com
 bobox.h:65: error: candidates
    are: wxComboBox::wxComboBox(wxWindow*, int, const wxString&, const wxPoint&,
    const wxSize&, const wxArrayString&, long int, const wxValidator&, const
    wxString&)
 
/pkg_comp/obj/pkgsrc/multimedia/vlc/default/.buildlink/include/wx-2.6/wx/gtk/com
 bobox.h:54: error:
                   wxComboBox::wxComboBox(wxWindow*, int, const wxString&, const
    wxPoint&, const wxSize&, int, const wxString*, long int, const wxValidator&,
    const wxString&)
 
 open.cpp:442: warning: `__comp_ctor' is deprecated (declared at
    
/pkg_comp/obj/pkgsrc/multimedia/vlc/default/.buildlink/include/wx-2.6/wx/sizer.h
    :788)
 
 open.cpp: In member function `wxPanel* wxvlc::OpenDialog::FilePanel(wxWindow*)
    ':
 open.cpp:566: error: call of overloaded `wxComboBox(wxPanel*&, <anonymous
    enum>, const char[1], wxPoint, wxSize, int, NULL)' is ambiguous
 
/pkg_comp/obj/pkgsrc/multimedia/vlc/default/.buildlink/include/wx-2.6/wx/gtk/combobox.h:65:
 error: candidates
    are: wxComboBox::wxComboBox(wxWindow*, int, const wxString&, const wxPoint&,
    const wxSize&, const wxArrayString&, long int, const wxValidator&, const
    wxString&)
 
/pkg_comp/obj/pkgsrc/multimedia/vlc/default/.buildlink/include/wx-2.6/wx/gtk/combobox.h:54:
 error:
                   wxComboBox::wxComboBox(wxWindow*, int, const wxString&, const
    wxPoint&, const wxSize&, int, const wxString*, long int, const wxValidator&,
    const wxString&)
 
 So, concluding, I can see why the compiler produces the error that it
 does, it can't be that NULL is somehow (void *)0 which would be
 incorrect for other reasons as well, and disambiguation of the NULL
 argument makes a lot of sense. Hence, my patch.
 
 >  Joerg
 -Olaf.
 -- 
 ___ Olaf 'Rhialto' Seibert      -- You author it, and I'll reader it.
 \X/ rhialto/at/xs4all.nl        -- Cetero censeo "authored" delendum esse.