#122 No programmatic way to detect SVF failures.

[Brian Geddes]

When using urjtag to play an SVF file, failures in SVF execution (ie TDO mismatches) are not detectable on the urjtag interface. The failures are logged, and so can been seen on the console. But when the failures occur (in urj_svf_compare_tdo()), urj_error_set() is never called, and urj_svf_run() always returns URJ_STATUS_OK. Thus an automated client of the API doesn't have a clean way to detect SVF programming failures.