Thanks for the advice.
I have cleaned the unneeded files, installed libctpl-dev, re-cloned and recompiled. If I select `Tools/Documentation Generator/Document All Symbols`, there is still a crash.
However if I select a single function there is no crash, but whether or not text is generated depends on the function parameters.
I now see that the problem occurs only if I select a function with an anonymous parameter e.g. `void collect_manager_notify_cb(FileData *fd, NotifyType type, gpointer)`
The Status pane of Geany shows something similar to `No setting applies to symbol "anon_parameter_5" of type "local" at line 1094.`
I could not find anything in the Geany documentation regarding anonymous or unnamed parameters. Have I missed something?