CEL_HEADER_V3 (Compact 2013)
3/28/2014
This structure precedes every logged event that is sent out through the logging mechanism.
Syntax
typedef struct {
DWORD Length:12;
DWORD CPU:4; DWORD ID : 14;
DWORD Reserved : 1;
DWORD fTimeStamp : 1;
} CEL_HEADER_V3, *PCEL_HEADER_V3;
Members
- Length
The lower 12 bits of the header holds the length, in bytes, of the event structure. This does not include the 32-bit length of the header structure or the 32-bit optional time stamp.
CPU
Specifies the number of the CPU that the event occurred on.If the event does not apply to any specific CPU, this value will be set to 0. Examples include data loss events and sync events.
If the CPU the event occurred on has a number greater than or equal to 15, the CPU number in the header will be set to 15. In that case, any timestamp or flag data in the event will be followed by a DWORD value containing the actual CPU number. As with the timestamp and flag values, the extra DWORD for the CPU number is not counted into the event size (length) value.
- ID
The next 14 bits of the header are used for the event identifier.
- Reserved
Reserved.
- fTimeStamp
The upper bit of the header is used to indicate whether or not a time stamp is present. If this bit is set, a 32-bit time stamp follows the structure and the value is given in tick counts. Otherwise, no time stamp follows.
Remarks
This structure is a single DWORD broken into several sections; it will be followed by a DWORD time stamp if the appropriate flag is set.
If you replace the event-tracking engine (Celog.lib) with your own, you should follow the same rules and include CEL_HEADER_V3 with each event. CEL_HEADER_V3 is attached to the data by CeLogData.
The format of the header has two forms depending on whether the event is a flagged event or not.
The following table shows the format of the non-flagged event header.
Data |
Description |
|---|---|
T |
Flag that indicates whether TIMESTAMP is added to the header (fTimeStamp) |
TIMESTAMP |
Time that an event was recorded |
ID |
Event that occurred (ID) |
LEN |
Length of the data (Length) |
DATA |
Raw data that follows the header |
The following table shows the format of the flagged event header.
Data |
Description |
|---|---|
T |
Flag that indicates whether TIMESTAMP is added to the header (fTimeStamp) |
CELID_FLAGGED |
Identifier that is used to determine whether the event has been flagged and the structure changed |
TIMESTAMP |
Time that an event was recorded |
ID |
Event that occurred (ID) |
FLAG |
User-provided flag use to flag the event |
LEN |
Length of the data (Length) |
DATA |
Raw data that follows the header |