Re: TreeView Question: how does one use TreeModelColumn<enum MyEnum>

[Robert Caryl <bob fis-cal com>]

Aren't the values declared in your enum Checksum_t in reality just a 
list of  integers?  Maybe I'm just dense here, but since that is the 
case, why not just declare your Gtk::TreeModelColumn as a data type 
int?  I *do* know that  the following won't even compile:

enum Checksum_t    {NONE, ADLER32, CRC32, MD5};
Checksum_t ADLER32 = 20;		// int to enum conversions are illegal and will not compile

I'm guessing that your segmentation fault happens because you've 
managed, by by passing Checksum_t to the Gtk::TreeModelColumn template, 
to fool the compiler into compiling a statement of code that attempts 
int to enum conversion.  As I said before, I'm probably just dense and 
don't understand what you're trying to accomplish.

Bob Caryl
> Here's what I would like to do:
> -------------------------------------------------------
> enum Checksum_t    {NONE, ADLER32, CRC32, MD5};
>
> class C_Columns : public Gtk::TreeModel::ColumnRecord {
> public:
>   Gtk::TreeModelColumn<Checksum_t> m_chksum_type;
>   C_Columns(){
>      add(m_chksum_type);
>   };
>  };
> -----------------------------------------------------------------------
> I run into a segfault when I try to assign a value e.g.
> C_Columns Columns;
> Checksum_t val = ADLER32;
> Glib::RefPtr<Gtk::TreeStore> refSelectedTreeStore;
> refSelectedTreeStore.clear();
> refSelectedTreeStore = Gtk::TreeStore::create(Columns);
> const Gtk::TreeIter & row_iter = refSelectedTreeStore->append();
> (*row_iter)[Columns.m_chksum_type] = val; // segfault
> ---------------------------------------------------------------------
> gdb tells me the bad news
> from /usr/include/glibmm-2.4/glibmm/value_custom.h:237:
>
> template <class T> inline
> void Value<T>::set(const typename Value<T>::CppType& data)
> {
>   // Assume the value is already default-initialized.  See
> value_init_func().
> =>  *static_cast<T*>(gobject_.data[0].v_pointer) = data;
> }
>
> (gdb) print gobject_
> $1 = {g_type = 0, data = {{v_int = 0, v_uint = 0, v_long = 0, v_ulong =
> 0, v_int64 = 0, v_uint64 = 0, v_float = 0, v_double = 0, v_pointer =
> 0x0}, {v_int = 0, v_uint = 0, v_long = 0, v_ulong = 0, v_int64 = 0,
> v_uint64 = 0, v_float = 0, v_double = 0, v_pointer = 0x0}}}
> --------------------------------------------------------------------
> I.e., the underlying gobject_'s data[] vector hasn't been initialized
> (value_init_func() probably hasn't been called).
>
> Enumeration types are the only data types I've difficulty with: all the
> other usual built-in C-types are fine, as are "proper" C++ objects.
>
> I'm running a default CentOS 4.3 installation, gtkmm-2.4, gcc 3.4.5.
> Does anyone have any suggestions?
>
> Thanks!
>
> Ed Leaver 
>
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