Total path for a Qspice simulation file : beware of the length!

Hello This is no question just a remark which , I believe, could be helpful for Qspice users: beware of the length of the total address path of a qspice simulation, or the total length of the model path: if this is too long (and I’m not quantitative here), the software could shut down abruptly without any warning.

Some years back, when I was writing console apps for Win-XP, I ran into the same problem. Some users were entering very long path strings that would crash the app or it would fail to work correctly. After a bit of research, I discovered that Win-XP paths could be up to 256 characters long. The fix was to make the input buffer very large (1-2KB) and test the path string length. I don’t know for sure but I assume later Win versions still allow path strings at least that long.


yes with windows 11 , I had put a simulation in a sub-sub-sub directory and Q spice shut down abruptly without any other sign.The simulation opened in Qspice but the shutdown happened when I tried to run it. So as my simulation worked flawlessly on another PC without any problem, I had to search for the reason and obviously , it was that. Not so sure that the length was 256, it seemed much less ; of course “one drive” and its extension does not help to that… so as I said beware…

On Windows, MAX_PATH is 260 including the null termination character, so 259 characters. Yeah, pretty short compared to UNIX’s 4096 or Linux’s unlimited path length.

I think there’s a way to program the Windows registry to make it longer, but no body does that so QSPICE doesn’t support it, either.