C'tors from templates

dsimcha dsimcha at yahoo.com
Sat Oct 31 13:39:14 PDT 2009


== Quote from dsimcha (dsimcha at yahoo.com)'s article
> == Quote from grauzone (none at example.net)'s article
> > dsimcha wrote:
> > > Is there a way to run a class's c'tor on a block of memory from a template
> > > function?  For example:
> > >
> > > C newClass(C, CtorArgs...)(CtorArgs args) {
> > >     // Allocate, initialize.
> > >     // Want to call the c'tor that takes type CtorArgs.
> > > }
> > Deeply hidden on the Digitalmars homepage, it hints _ctor() and shows
> > how to correctly construct an object (if you're using dmd):
> > http://www.digitalmars.com/techtips/class_objects.html
> Yeah, I had thought of this, but apparently it doesn't work anymore.  This is
> called excessive encapsulation--making things so opaque that, when someone really
> knows what they're doing and has a good reason to mess around with the internals,
> they still can't.  I'll file an enhancement requesting that this be put back.

Never mind, I realized I was doing two things wrong:

1.  It changed from _ctor to __ctor.
2.  The class needs to define a c'tor  If it doesn't, then there's no default
__ctor() that takes no args.  However, this is easy to check for in a static if
statement.



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