求解释

#ifdef __cplusplus
PR_BEGIN_EXTERN_C
#endif
eMBErrorCode eMBRTUInit( UCHAR slaveAddress, UCHAR ucPort, ULONG ulBaudRate,
eMBParity eParity );
void eMBRTUStart( void );
void eMBRTUStop( void );
eMBErrorCode eMBRTUReceive( UCHAR * pucRcvAddress, UCHAR ** pucFrame, USHORT * pusLength );
eMBErrorCode eMBRTUSend( UCHAR slaveAddress, const UCHAR * pucFrame, USHORT usLength );
BOOL xMBRTUReceiveFSM( void );
BOOL xMBRTUTransmitFSM( void );
BOOL xMBRTUTimerT15Expired( void );
BOOL xMBRTUTimerT35Expired( void );
#ifdef __cplusplus
PR_END_EXTERN_C
#endif