ABLE Ap1400 - Page 40

Ref: "Ap1400ProgGuide1_2.docx" Page 40 of 42
Document Revision: “1.2”
Document Date: “9 Apr. 2013”
SendCtrl (Continued)
Example
The following example shows a ctrl call to retrieve the print
buffer status
TCHAR cReturn;
int iRetLen=sizeof(TCHAR);
//Check the buffer state
DWORD dwStatusCode=SendCtrl(iHandle,
USB_TYPE_CLASS|USB_RECIP_DEVICE|USB_ENDPOINT_IN,
USB_BUFFERSTATE,
0,
0,
&iRetLen,
&cReturn);
if(dwStatusCode!=ERROR_SUCCESS)
{
TRACE(_T("Buffer state get Failed...\n"));
CString csError;
csError.Format(_T("GetBufferState failed - Reason=%d."),
dwStatusCode);
AfxMessageBox(csError,MB_ICONSTOP|MB_OK);
bError=TRUE;
continue;
}
//if the error code is OK the check the return
if(cReturn==BUFFER_BUSY)
{
TRACE(_T("Buffer state reports BUFFER_BUSY...\n"));
//Wait for a small period and retry
iMaxTime+=BUFFER_WAIT_PERIOD;
Sleep(BUFFER_WAIT_PERIOD);
continue;
}
else if(cReturn==BUFFER_CLEAR)
{
iMaxTime=0;
TRACE(_T("Buffer state reports BUFFER_CLEAR...\n"));
//Continue printing
//……
}