# Debug Aids For VVP

Debugging vvp can be fiendishly difficult, so there are some built in debugging aids. These are enabled by setting the environment variable VVP_DEBUG to the path to an output file. Then, various detailed debug tools can be enabled as described below.

- .resolv

The .resolv can print debug information along with a label by specifying the debug output label on the .resolv line:

    .resolv tri$<label>

In this case, the “$” character directly after the “tri” enables debug dumps for this node, and the <label> is the label to prepend to log messages from this node.