ngspice mixed signal support broken

[mattvenn]

Describe the bug

In release 2025.07 this worked, but in 2026.05 it fails like this:

https://sourceforge.net/p/ngspice/bugs/843/

Following from that discussion, it looks like ngspice is not being built from the official sources.

[gatk555]

It is not all of mixed-signal, just Verilator integration, and assuming the ngspice-46 code is used, is an Ngspice bug. Already fixed in development.

[hpretl]

@gatk555 Do you know which ngspice commit fixes this?

[gatk555]

e42a9e6b5c2ea61debd257678ab6a442233693a1

But a rare issue, I would wait for ngspice-47 to update.

[utz12]

Mixed signal simulation with Icarus Verilog also seems to be broken for a while now. Error message:

Instance: a1   Message: ERROR: no entry function in ivlng
Instance: a1   Message: /foss/tools/ngspice/lib/ngspice/ivlng.so: undefined symbol: Cosim_setup

Maybe a wrongly compiled ivlng.so?

[hpretl]

@utz12 I and Claude have now found the bug, and it will be fixed in the next image release. The fix is done in cbd6634. The regression is caused by us building ngspice and then the shared lib. Due to a weakness in ngspice's Makefile the bug is triggered, but we have now solved it on our side.

This is related to the iverilog bug. The verilator bug is something else and needs to be fixed upstream by the next ngspice release.