Re: retrieving templatized object via singleton getInstance using generic template parameters

Wed, 06 Jun 2007 03:21:15 -0000
On Jun 5, 8:05 pm, wrote:

I want to call a singleton getInstance function to retrieve a
templatized object without knowing what types were used to create the
singleton object in the first call to getInstance. How can I do this
non-intrusively -- I.e., without, for example, typedef'ing the types
in every compilation unit?


Our code base has assert macros that need to reboot the system after
notifying components via a single templatized Component object that
contains the IPC object. I made the macro call a reboot function, but
that function needs to access the IPC object. I want to singleton'ize
the Component object to provide access to the IPC object, but don't
want to hand-code the template parameters in each compilation unit for
each getInstance call.


// I want to call retrieve a templatized object via a call to
// without supplying the objects template parameters.
// Is there any way to do this, perhaps using template meta-
programming (TMP) techniques?

#include <string>
#include <iostream>

using namespace std;

template <typename T1, typename T2>
class Component


      static Component<T1, T2> getInstance()
         static Component<T1, T2> t;
         return t;


int main()

   // after the initial call to getInstance, here

   Component<int, string> & r1 = Component<int,

   // I then want to call getInstance to obtain the same Component
without specifying the template params.

   Component<something generic> & r2 = Component<something


I may be able to, instead, simple singleton'ize the internal IPC
object I'm trying to use, which isn't templatized, but I'm still very
curious as to how a templatized object can be retrieved via
getInstance without providing the objects template parameters.

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