Locking Files

tcov Enhanced uses a simple file-locking mechanism for updating the block coverage data file. It employs a single file created in the same directory as the tcovd file. The file name is tcovd.temp.lock. If execution of the program compiled for coverage analysis is manually terminated, then the lock file must be deleted manually.

The locking scheme does an exponential back-off if there is a contention for the lock. If, after five tries, the tcov runtime cannot acquire the lock, it gives up and the data is lost for that run. In this case, the following message is displayed:

tcov_exit: temp file exists, is someone else running this executable?