新建 文本文档.txt

VC的一个打印程序

GUID hidGuid; 
HidD_GetHidGuid (&hidGuid); 
HDEVINFO deviceInfo = SetupDiGetClassDevs ( &hidGuid, 0, 0, DIGCF_PRESENT | 
 DIGCF_INTERFACEDEVICE)); 
   if ( !deviceInfo ) return m_deviceCount; 
   // Setup data for HID devices enumeration: 
  BOOL isSuccess = FALSE;    // Note: You must use BOOL...NOT...***bool***with WIN32 API calls; 
  unsigned long bytes = 0;   
  SP_INTERFACE_DEVICE_DATA deviceData; 


   memset( &deviceData, 0, sizeof(SP_INTERFACE_DEVICE_DATA) );   
   deviceData.cbSize = sizeof (SP_INTERFACE_DEVICE_DATA); 
   PSP_INTERFACE_DEVICE_DETAIL_DATA deviceInterfaceData = 0;   
   size_t size = sizeof(SP_INTERFACE_DEVICE_DETAIL_DATA); 
   for ( int i = 0; i < PT_MAX_USB_DEVICES; i++ )   
   {       
       // Get each HID device attached...we will ignore those   
       isSuccess = SetupDiEnumInterfaceDevice ( deviceInfo, 0, &hidGuid, 
i,&deviceData);     


       if ( !isSuccess ) 
      { 
            if ( ERROR_NO_MORE_ITEMS == GetLastError() ) 
                break; 
           else 
                continue; 
       } 
       // Get specified device interface information. 
       // Note: We call this 2x. The first time is  to acquire the amount 
of memory we will need to store the device info in. 


       SetupDiGetInterfaceDeviceDetail( deviceInfo, &deviceData,  0,  0,   
&bytes, 0);       
       deviceInterfaceData = (PSP_INTERFACE_DEVICE_DETAIL_DATA) new BYTE[bytes];       // Create the device interface data structure... 


       if ( !deviceInterfaceData ) 
       { 
             outOfMemory(); 
             SetupDiDestroyDeviceInfoList( deviceInfo ); 
             return m_deviceCount; 
       } 
       memset( deviceInterfaceData, 0, bytes ); 
       deviceInterfaceData->cbSize  = size;       // Retrieve the device 
interface information: 
       isSuccess = SetupDiGetInterfaceDeviceDetail ( deviceInfo,   
&deviceData, deviceInterfaceData, bytes, &bytes, 0); 
       if ( !isSuccess ) 
       { 
            reportLastError( __FILE__, __LINE__ ); 
            delete [] (BYTE*)deviceInterfaceData; 
            SetupDiDestroyDeviceInfoList( deviceInfo ); 
            return m_deviceCount; 
       } 
       // Open device for both read and write... 
       HANDLE hidDevice = CreateFile( deviceInterfaceData->DevicePath,       
               //communication port name 
                                      GENERIC_READ    | GENERIC_WRITE,       
      //read/write types 
                                      FILE_SHARE_READ | FILE_SHARE_WRITE,   
    //comm devices must be opened with exclusive access 
                                      0,                                     
                //no security attributes 
                                      OPEN_EXISTING,                         
                //communication devices must use OPEN_EXISTING 
                                      0,                                     
                //Sync I/O 
                                      0);                             
       if ( INVALID_HANDLE_VALUE == hidDevice) 
       { 
            delete [] (BYTE*)deviceInterfaceData; 
            continue; 
       }