What is the C++ command to call a procedure (residing in a calling app) by its address, in a function that accepts the address (of the function to be called) as an argument?

Usage: To call a VB procedure by its address using a C++ DLL.
e.g.

VB Code:
  1. Private declare sub CallByProcAddress Lib "xxx" (ByVal lpfnProcAddress as Long)

  2.  
  3. CallByProcAddress AddressOf TheProc

Sorry, I'm a C++ n00b.