lgo_Poll()

Poll for the presence of control or data events.

#include "laygo.h"

LEvent  lgo_Poll
    (
        LCid             cid,
        LBufferSize *    count
    );

lgo_Poll() tests for the receipt of control and data events. If lgo_Read() or lgo_ReadSpecial() fails with an error code of lgo_ERROR_BUFFER_SIZE, an application may call lgo_Poll() to determine the number of bytes of data waiting to be read.

If successful, lgo_Poll() returns a non-negative value indicating the type of control event received. Possible successful return values are:

• lgo_EVENT_CONNECT_REQUEST
• lgo_EVENT_CONNECTED
• lgo_EVENT_CONNECT_TIMEOUT
• lgo_EVENT_CONNECT_ACCEPT
• lgo_EVENT_CONNECT_REFUSE
• lgo_EVENT_DISCONNECTED
• lgo_EVENT_DISCONNECTING
• lgo_EVENT_DISCONNECT_REQUEST
• lgo_EVENT_DISCONNECT_TIMEOUT
• lgo_EVENT_DISCONNECT_CONFIRMATION
• lgo_EVENT_RESETTING
• lgo_EVENT_RESET_COMPLETED
• lgo_EVENT_RESET_TIMEOUT
• lgo_EVENT_XON_REQUEST
• lgo_EVENT_XOFF_REQUEST
• lgo_EVENT_DATA_OK
• lgo_EVENT_DATA_LENGTH_ERROR
• lgo_EVENT_DATA_CRC_ERROR
• lgo_EVENT_DATA_ABORTED_FRAME
• lgo_EVENT_PROTOCOL_MESSAGE
• lgo_EVENT_DATA_SPECIAL

Otherwise, it returns a negative value indicating the reason it failed. Possible unsuccessful return values are:

• lgo_ERROR_INVALID_CID
• lgo_ERROR_INVALID_COMMAND
• lgo_ERROR_NOTHING_WAITING

lgo_Event()

if ((event = lgo_Poll(cid, &bufferSize)) < 0)
{
    /* process error */
}
else
{
    switch(event)
    {
        case lgo_EVENT_DATA_OK:

            /* read good data */
            break;

        case lgo_EVENT_DATA_LENGTH_ERROR:
        case lgo_EVENT_DATA_CRC_ERROR:
        case lgo_EVENT_DATA_ABORTED_FRAME:

            /* discard bad data */
            break;

        default:

            /* process events */
            break;
    }
}