• double*
  return voltage value
• double
  actual time
• char*
  node name
• int
  identification number of calling ngspice shared lib
• void*
  return pointer received from caller

Ask for a VSRC EXTERNAL voltage value. The independent voltage source (see Chapt. 4.1) with EXTERNAL option allows to set a voltage value to the node defined in the netlist and named here at the time returned by the simulator.