```
bitcoind -par=1
```

Excerpt from the `debug.log`:

```
Using 0 threads for script verification
```

Zero? I guess not ;)
for (const auto& name : names) {
            BlockFilterType filter_type;
            if (!BlockFilterTypeByName(name, filter_type)) {
                return InitError(strprintf(_("Unknown -blockfilterindex value %s.").translated, name));
            }
            g_enabled_filter_types.push_back(filter_type);
        }
    }
    
    if (gArgs.GetArg("-prune", 0)) {
        if (gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX))
            return InitError(_("Prune mode is incompatible with -txindex.").translated);
        if (!g_enabled_filter_types.empty()) {
            return InitError(_("Prune mode is incompatible with -blockfilterindex.").translated);
        }
    }
    
    size_t nUserBind = gArgs.GetArgs("-bind").size() + gArgs.GetArgs("-whitebind").size();
    if (nUserBind != 0 && !gArgs.GetBoolArg("-listen", DEFAULT_LISTEN)) {
        return InitError("Cannot set -bind or -whitebind together with -listen=0");
    }
    
    int nBind = std::max(nUserBind, size_t(1));
    nUserMaxConnections = gArgs.GetArg("-maxconnections", DEFAULT_MAX_PEER_CONNECTIONS);
    nMaxConnections = std::max(nUserMaxConnections, 0);
    
    
    nFD = RaiseFileDescriptorLimit(nMaxConnections + MIN_CORE_FILEDESCRIPTORS + MAX_ADDNODE_CONNECTIONS);
#ifdef USE_POLL
    int fd_max = nFD;