From: ian-news@this.is.invalid   
      
   Dave Abrahams wrote:   
   > on Tue Dec 18 2012, Ian Collins  wrote:   
   >   
   >> I would certainly dispute the impact of singletons on testability.   
   >   
   > You would?   
   >   
   >> Anyway, I encountered another real life use case where DI can't be   
   >> used today: functions called from an external library.  I have a   
   >> set of functions called from an RPC library that use a singleton   
   >> connection to access another process.  The calling library has no   
   >> knowledge of this connection, so it can't be passed.  I expect this   
   >> situation isn't uncommon.   
   >   
   > If the calling library doesn't let you pass data through to these   
   > functions, you can still templatize the functions and get access to   
   > the "singleton" through the template parameter.   
      
   Not in this case, the caller in this example gets the function's   
   address from a UNIX dlsym call, so the functions have to be extern "C"   
   which rules out function templates.  Now I could add another level of   
   indirection..   
      
   --   
   Ian Collins   
      
      
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