This function can discard all characters from the output or input buffer of a specified communications resource. It can also terminate pending read or write operations on the resource.
At a Glance
| Header file: | Winbase.h |
| Windows CE versions: | 1.0 and later |
Parameters
Syntax
BOOL PurgeComm(HANDLE hFile, DWORD dwFlags);
hFile
[in] Handle to the communications resource. The CreateFile function returns this handle.
dwFlags
[in] Specifies the action to take. This parameter can be a combination of the following values:
| Value | Description |
| PURGE_TXABORT | Terminates all outstanding overlapped write operations and returns immediately, even if the write operations have not been completed. |
| PURGE_RXABORT | Terminates all outstanding overlapped read operations and returns immediately, even if the read operations have not been completed. |
| PURGE_TXCLEAR | Clears the output buffer (if the device driver has one). |
| PURGE_RXCLEAR | Clears the input buffer (if the device driver has one). |
Return Values
Nonzero indicates success. Zero indicates failure. To get extended error information, call GetLastError.
Remarks
If a thread uses PurgeComm to flush an output buffer, the deleted characters are not transmitted. To empty the output buffer while ensuring that the contents are transmitted, call the FlushFileBuffers function (a synchronous operation). Note, however, that FlushFileBuffers is subject to flow control but not to write time-outs, and it will not return until all pending write operations have been transmitted.
See Also