The class test {public: void fun () {}} 

The class layerManager 
{
Public: 
The static layerManager * getlayerManagerHandler () 
{
The static layerManager& Rh=null; 
if(! Rh) 
{
Rh=new layerManager; 
} 
Return rh; 
} 
Template 
T * getLayer (const STD: : string layername) 
{
The test * p=new test; 
Return dynamic_cast & lt; T> (p); 
} 
Void fun () {} 
Private: 
LayerManager () {} 
~ layerManager () {} 
}; 

# define RES (name type) 
LayerManager: : getlayerManagerHandler () - & gt; Fun (); \ 
LayerManager: : getlayerManagerHandler () - & gt; GetLayer (name); 

Int main () 
{
STD: : string ss="a"; 
The test * p=RES (ss, test) 
p-> Fun (); 
Retrun 0; 
} 

CodePudding user response:

Comma expression, comma expression of value is the statement on the right, so you can like this:

 # define RES (name, type) \ 
(\ 
LayerManager: : getlayerManagerHandler () - & gt; Fun (),, 
LayerManager: : getlayerManagerHandler () - & gt; GetLayer (name) \ 
) 

CodePudding user response:

More conventional practice is layered and function, as follows:

 template 
T * fun_ (const STD: : string & amp; SLayerName) 
{
LayerManager: : getlayerManagerHandler () - & gt; Fun (); 
Return layerManager: : getlayerManagerHandler () - & gt; GetLayer (sLayerName); 
} 

# define RES (name, type) fun_ & lt; Type> (name)