Re: [TCLCORE] CONST86 and extensions

[Jan N. <jan...@gm...>]

2009/7/16 Donald G Porter <don...@ni...>:
> That said, these all appear to be calls to Tcl_GetObjType() which we
> have increasing agreement is a dicey thing at best for extensions to
> be calling.  Especially bad that there appears to be no safety checks
> for NULL returns.
>
> If Thread really needs access to the internals of the Tcl_ObjTypes
> defined by Tcl itself, should Thread really get on a path to just
> become part of Tcl?

Well, I looked at the code, and the Thread extension is not one of
the 'bad guys' which violate the API assumtions. Just putting
a "const" here and there can eliminate all warnings, without
introducing unsafe type casts or using the CONST86 macro.

I think, calling Tcl_GetObjType() is not bad, it is bad when
an extension writes to the memory where the returned pointer
is pointed to. Thead doesn't do that, it uses Tcl_GetObjType()
what it is meant for: a fast shortcut to check whether some
object is of a specific type or not. That's fully legal.

Regards,
        Jan Nijtmans