SystemVerilog [Virtual interface instantiating]

Question

Can I instantiate virtual interface? what is the syntax? for example : if I've the following interface:

interface if ( input in1, in2, output out1, out2 ); endinterface

virtual interface if vif;

can I instantiate vif ?

Answer 1

Virtual interfaces can only have , another virtual interface or a instance of the interface or null assigned to it .

ifs m_ifs () ; 

vifs = m_ifs ;  // valid 
vifs = vifs1 ;  // valid 
vifs = null ( this is the default value if unassigned) 

If you mean 
vifs = new () or  new (if ) ; 

something like the statement above is not allowed .

You could do this instead

Class interface_container { 

virtual interface ifs vifs ; 

} ; 

interface_container m_interface_container[2] ; 

m_interface_container[0] = new () ; 
m_interface_container[1] = new () ; 

So now you have 2 instances of vif within instances of the two class BUT

you still have to assign a interface instance to them . Interface instance itself cannot be dynamic as they represent physical connections.

m_interface_container[0].vifs = m_ifs ; 
m_interface_container[1].vifs = m_ifs ; 

So there can be many virtual interfaces , yet all the virtual interfaces ( if not null ) will eventually point to some fixed set of interface instances.