Статьи Королевства Дельфи


Просмотрщик событий из журнала событий Windows. - часть 2


The ReadEventLog function reads a whole number of entries from the specified event log. The function can be used to read log entries in chronological or reverse chronological order. BOOL ReadEventLog ( HANDLE hEventLog , // handle to event log DWORD dwReadFlags,, // how to read log DWORD dwRecordOffset, // offset of first record LPVOID lpBuffer, // buffer for read data DWORD nNumberOfBytesToRead,// bytes to read DWORD * pnBytesRead, // number of bytes read DWORD * pnMinNumberOfBytesNeeded // bytes required );

Параметры: hEventLog[in] Handle to the event log to read. This handle is returned by the OpenEventLog function. dwReadFlags [in] Specifies how the read operation is to proceed. This parameter must include one of the following values.

ValueMeaning
EVENTLOG_SEEK_READThe read operation proceeds from the record specified by the dwRecordOffset parameter. This flag cannot be used with EVENTLOG_SEQUENTIAL_READ.
EVENTLOG_SEQUENTIAL_READ The read operation proceeds sequentially from the last call to the ReadEventLog function using this handle. This flag cannot be used with EVENTLOG_SEEK_READ.

If the buffer is large enough, more than one record can be read at the specified seek position; you must specify one of the following flags to indicate the direction for successive read operations.
ValueMeaning
EVENTLOG_FORWARDS_READThe log is read in chronological order. This flag cannot be used with EVENTLOG_BACKWARDS_READ.
EVENTLOG_BACKWARDS_READThe log is read in reverse chronological order. This flag cannot be used with EVENTLOG_FORWARDS_READ.
dwRecordOffset[in] Specifies the log-entry record number at which the read operation should start. This parameter is ignored unless dwReadFlags includes the EVENTLOG_SEEK_READ flag. lpBuffer [out] Pointer to a buffer for the data read from the event log. This parameter cannot be NULL, even if the nNumberOfBytesToRead parameter is zero. The buffer will be filled with an EVENTLOGRECORD structure. nNumberOfBytesToRead[in] Specifies the size, in bytes, of the buffer. This function will read as many whole log entries as will fit in the buffer; the function will not return partial entries, even if there is room in the buffer. pnBytesRead[out] Pointer to a variable that receives the number of bytes read by the function. pnMinNumberOfBytesNeeded[out] Pointer to a variable that receives the number of bytes required for the next log entry. This count is valid only if ReadEventLog returns zero and GetLastError returns ERROR_INSUFFICIENT_BUFFER. Return Values:
В случае удачи, функция возвращает ненулевое значение. В противном случае будет возвращен 0. Для более подробной информации смотрите GetLastError.
Примечание:
When this function returns successfully, the read position in the error log is adjusted by the number of records read. Only a whole number of event log records will be returned.
Note
The configured filename for this source may also be the configured filename for other sources (several sources can exist as subkeys under a single logfile). Therefore, this function may return events that were logged by more than one source.




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