I have made an update to the ngspice shared library interface.
Three new callback function have been added for transient simulation synchronization.
The callback function interface has been changed slightly by adding a identification number. You will have to adapt your existing code to this feature.
ngSpice_Init_Sync() has been enhanced to transfer the callback pointers and the ident number.
Please have a look at the actual ngspice manual, chapter 19.6, for details.
Updated demo files will follow soon.