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The following examples only illustrate the implementation of specific functionalities and are not intended to provide a solution to implementing a complete user plug-in.
Response to change in data base
To respond to changes in the data base, a corresponding callback function (OnDatabaseChanged) must be registered, for example, in the export function DLL_vInit. Please note that this is not possible during simulation.
// Register OnDatabaseChanged. if(CAND_enRegisterCallback(OnDatabaseChanged, CAND_enDBChanged, CAND_hNullHandle(), 0) == CAND_nERR_OK) { // Registration was successful. } |
Unregistration can be implemented in the export function DLL_vDeInit.
// Deregister OnDatabaseChanged. if(CAND_enUnRegisterCallback(OnDatabaseChanged, CAND_enDBChanged, CAND_hNullHandle(), 0) == CAND_nERR_OK) { // Deregistration was successful. } |
The callback function must have the following structure:
ANSI_C void USERDLL_CALL OnDatabaseChanged(CAND_tenDBChangedReason iReason, CAND_tHandle hObject) { // Insert code here for response to change in database. } |
Each time the data base is changed, this function is called, e.g. if a new data base is loaded or a data base object is changed.
Example: Actions before sending a message
To generate notifications before a message is sent to the bus, a “pre-transmit” callback can be registered:
// Register OnPreTransmitMsg. if(CAND_enRegisterCallback(OnPreTransmitMsg, CAND_enPreTransmit, m_hRegMsg, 0) == CAND_nERR_OK) { // Registration was successful. } |
If the callback is not used anymore, it must be unregistered:
if(CAND_enUnRegisterCallback(OnPreTransmitMsg, CAND_enPreTransmit, m_hRegMsg, 0) == CAND_nERR_OK) { // Deregistration was successful. } |
The following implementation of the callback function causes the signal value of the signal NMOT to be incremented before sending the message MS_308h.
ANSI_C unsigned char USERDLL_CALL OnPreTransmitMsg( CAND_tHandle hMsg, CAND_tstCanMessage* pstMsg, DWORD dwUserData) { // Call handle on message "MS_308h". CAND_tHandle hMs308h = CAND_hFindObject(NULL, NULL, "MS_308h", -1, NULL, CAND_hNullHandle());
// Call handle for Signal from the message. CAND_tHandle hAliveCounter = CAND_hGetSignalByName(hMs308h, "NMOT");
// Call Signal value QWORD qwSigVal = 0; if (CAND_enGetSigData(hAliveCounter, &qwSigVal, sizeof(qwSigVal)) == CAND_nERR_OK) { // Increase and rewrite Signal value qwSigVal++;
if(CAND_enSetSigDataHex(hAliveCounter, qwSigVal) == CAND_nERR_OK) { // Signal value was set. } } return 1; } |