National Instruments CAN 372139B-01 - Manual (Page 266)

Chapter 6 Automotive Diagnostic Command Set API for C
Automotive Diagnostic Command Set User Manual 6-102 ni.com
Return Value
The return value indicates the function call status as a signed 32-bit integer. Zero means the
function executed successfully. A negative value specifies an error, which means the function
did not perform the expected behavior. A positive value specifies a warning, which means the
function performed as expected, but a condition arose that may require attention.
Use the ndStatusToString function to obtain a descriptive string for the return value.
Description
This function executes the ReportSupportedDTCs subfunction of the UDS
ReadDiagnosticTroubleCodeInformation service and reads all supported DTCs from the
ECU memory.
For further details about this service, refer to the ISO 15765-3 standard.