[Ngspice-bugs] Segfault with remcirc and ngSpice_Init

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Dear developers,

The attached C++ source demonstrates a curious segfault. The code calls 
ngSpice_Init, runs a circuit sim, then calls remcirc to delete the 
circuit, then calls ngSpice_Init again and runs another circuit, at 
which point there is a crash. Removing either the remcirc command or the 
second ngSpice_Init call fixes it.

I would hope that calling ngSpice_Init again would reset ngspice back to 
its default state and set the new callbacks, but apparently it leaves 
some old memory around? Alternatively if ngSpice_Init is not supposed to 
be called again, I would expect there to be a shutdown function 
available that cleans up, allowing ngSpice_Init to be called once more.

It seems KiCad avoids this problem by loading libngspice.so at runtime 
using dlopen() each time a simulation is run, which implicitly resets 
ngspice's internal state. It would be good if there were a way to reset 
the state in the case of compile-time linking as well (if I missed an 
existing way to do this, I'd be pleased to find out!).

Cheers,


Sean Leavey