Activate debug printing by setting the environment symbol TOCHNOG_DEBUG to yes.
Printing can be limited by setting the following environment symbols:
| environment symbol | purpose |
| TOCHNOG_ELEMENT element_number | Printing for specific element only. |
| TOCHNOG_ICONTROL control_number | Printing for specific control index only. |
| TOCHNOG_ITERATION iteration_number | Printing for specific iteration only. |
| TOCHNOG_NODE node_number | Printing for specific node only. |
| TOCHNOG_ROUTINE routine_name | Printing for specific routine only. |
You also can set the environment variable TOCHNOG_REPORT_ROUTINE. Then tn reports the routines it passes.
After a calculation, the entire database can be printed by using control_print_database index -everything. This prints, besides the normal user variables, also internal variables.