 ReadAdu232
This function reads data from the ADU RS232 pipe. The number of bytes read is returned
in lpNumberOfBytesRead.
The handle value must be the value returned by the open call.
ADU RS232 data blocks are limited to 40 characters in length.
C Declaration:
int __stdcall ReadAdu232(void * hDevice,
const void * lpBuffer,
unsigned long nNumberOfBytesToRead,
unsigned long * lpNumberOfBytesRead,
unsigned long iTimeout);
Visual Basic Declaration:
Declare Function ReadAdu232 Lib "AduHid.DLL" _
(ByVal aduHandle As Long, ByVal lpBuffer As String, _
ByVal lNumberOfBytesToRead As Long, _
ByRef lBytesRead As Long, ByVal iTimeout As Long) As Long
Arguments:
| Argument |
Type |
Value |
Description |
| hDevice |
void * |
value from open call |
handle to the device |
| lpBuffer |
const char * |
address of buffer |
buffer to receive data |
| nNumberOfBytesToRead |
unsigned long |
> 0 |
number of bytes to read |
| lpNumberOfBytesRead |
unsigned long * |
|
number of bytes read |
| iTimeout |
unsigned long |
|
milli-seconds to wait |
A non-zero iTimeout value can only be supplied if timeout processing was activated during
the open call. (ie. a non-zero iTimeout value was passed into the open function)
Return Codes:
| Value |
Description |
| 0 |
call failed |
| other |
call succeeded |
Note: call GetLastError to get more information about a failed read operation.
Programming Notes
The Adu232 pipe uses hex zero bytes internally as a transmission delimiter. No hex zero
bytes are passed back to the calling application. An application that intends to use the
response as a zero-terminated string must allocate an extra byte for the buffer and
zero-fill the buffer before the ReadAdu232 call. |