The warning that 'fBuffer' may be used uninitialized seems to be from GCC inlining 'static' functions - as the warning is reported in PrepareFrame(), but the definition of fBuffer is in LoRaMacMcpsRequest()
PrepareFrame() is called by Send() which is called from LoRaMacMcpsRequest():
LoRaMacStatus_t LoRaMacMcpsRequest( McpsReq_t* mcpsRequest, bool allowDelayedTx )
{
GetPhyParams_t getPhy;
PhyParam_t phyParam;
LoRaMacStatus_t status = LORAMAC_STATUS_SERVICE_UNKNOWN;
LoRaMacHeader_t macHdr;
VerifyParams_t verify;
uint8_t fPort = 0;
void* fBuffer; // <=== *** Defined here
uint16_t fBufferSize;
int8_t datarate = DR_0;
bool readyToSend = false;
if( mcpsRequest == NULL )
{
return LORAMAC_STATUS_PARAMETER_INVALID;
}
if( LoRaMacIsBusy( ) == true )
{
return LORAMAC_STATUS_BUSY;
}
macHdr.Value = 0;
memset1( ( uint8_t* ) &MacCtx.McpsConfirm, 0, sizeof( MacCtx.McpsConfirm ) );
MacCtx.McpsConfirm.Status = LORAMAC_EVENT_INFO_STATUS_ERROR;
// AckTimeoutRetriesCounter must be reset every time a new request (unconfirmed or confirmed) is performed.
MacCtx.AckTimeoutRetriesCounter = 1;
switch( mcpsRequest->Type )
{
case MCPS_UNCONFIRMED:
{
readyToSend = true;
MacCtx.AckTimeoutRetries = 1;
macHdr.Bits.MType = FRAME_TYPE_DATA_UNCONFIRMED_UP;
fPort = mcpsRequest->Req.Unconfirmed.fPort;
fBuffer = mcpsRequest->Req.Unconfirmed.fBuffer;
fBufferSize = mcpsRequest->Req.Unconfirmed.fBufferSize;
datarate = mcpsRequest->Req.Unconfirmed.Datarate;
break;
}
case MCPS_CONFIRMED:
{
readyToSend = true;
MacCtx.AckTimeoutRetries = MIN( mcpsRequest->Req.Confirmed.NbTrials, MAX_ACK_RETRIES );
macHdr.Bits.MType = FRAME_TYPE_DATA_CONFIRMED_UP;
fPort = mcpsRequest->Req.Confirmed.fPort;
fBuffer = mcpsRequest->Req.Confirmed.fBuffer;
fBufferSize = mcpsRequest->Req.Confirmed.fBufferSize;
datarate = mcpsRequest->Req.Confirmed.Datarate;
break;
}
case MCPS_PROPRIETARY:
{
readyToSend = true;
MacCtx.AckTimeoutRetries = 1;
macHdr.Bits.MType = FRAME_TYPE_PROPRIETARY;
fBuffer = mcpsRequest->Req.Proprietary.fBuffer;
fBufferSize = mcpsRequest->Req.Proprietary.fBufferSize;
datarate = mcpsRequest->Req.Proprietary.Datarate;
break;
}
default: // <=== *** this potentially leaves fBuffer uninitialised
break;
}
// Get the minimum possible datarate
getPhy.Attribute = PHY_MIN_TX_DR;
getPhy.UplinkDwellTime = MacCtx.NvmCtx->MacParams.UplinkDwellTime;
phyParam = RegionGetPhyParam( MacCtx.NvmCtx->Region, &getPhy );
// Apply the minimum possible datarate.
// Some regions have limitations for the minimum datarate.
datarate = MAX( datarate, ( int8_t )phyParam.Value );
if( readyToSend == true )
{
if( MacCtx.NvmCtx->AdrCtrlOn == false )
{
verify.DatarateParams.Datarate = datarate;
verify.DatarateParams.UplinkDwellTime = MacCtx.NvmCtx->MacParams.UplinkDwellTime;
if( RegionVerify( MacCtx.NvmCtx->Region, &verify, PHY_TX_DR ) == true )
{
MacCtx.NvmCtx->MacParams.ChannelsDatarate = verify.DatarateParams.Datarate;
}
else
{
return LORAMAC_STATUS_PARAMETER_INVALID;
}
}
status = Send( &macHdr, fPort, fBuffer, fBufferSize, allowDelayedTx ); // <=== *** used here
