UpdateTrace macro

The UpdateTrace function updates the property setting of the specified event tracing session.

The ControlTrace function supersedes this function.

Syntax

void UpdateTrace(
   a,
   b,
   c
);

Parameters

a

Handle to the event tracing session to update, or NULL. You must specify SessionHandle if SessionName is NULL. However, ETW ignores the handle if SessionName is not NULL. The handle is returned by the StartTrace function.

b

Pointer to a null-terminated string that specifies the name of the event tracing session to update, or NULL. You must specify SessionName if SessionHandle is NULL.

To specify the NT Kernel Logger session, set SessionName to KERNEL_LOGGER_NAME.

c

Pointer to an initialized EVENT_TRACE_PROPERTIES structure.

On input, the members must specify the new values for the properties to update. For information on which properties you can update, see Remarks.

On output, the structure members contains the updated settings and statistics for the event tracing session.

Return Value

None

Remarks

Controllers call this function.

On input, the members must specify the new values for the properties to update. You can update the following properties.

Member Use
EnableFlags Set this member to 0 to disable all kernel providers. Otherwise, you must specify the kernel providers that you want to enable or keep enabled. Applies only to NT Kernel Logger sessions.
FlushTimer Set this member if you want to change the time to wait before flushing buffers. If this member is 0, the member is not updated.
LogFileNameOffset Set this member if you want to switch to another log file. If this member is 0, the file name is not updated. If the offset is not zero and you do not change the log file name, the function returns an error.
LogFileMode Set this member if you want to turn EVENT_TRACE_REAL_TIME_MODE on and off. To turn real time consuming off, set this member to 0. To turn real time consuming on, set this member to EVENT_TRACE_REAL_TIME_MODE and it will be OR'd with the current modes.
MaximumBuffers Set set this member if you want to change the maximum number of buffers that ETW uses. If this member is 0, the member is not updated.
 

For private logger sessions, you can only update LogFileNameOffset and FlushTimer.

If you are using a newly initialized EVENT_TRACE_PROPERTIES structure, the only members you need to specify, other than the members you are updating, are Wnode.BufferSize, Wnode.Guid, and Wnode.Flags.

If you use the property structure you passed to StartTrace, make sure the LogFileNameOffset member is 0 unless you are changing the log file name.

If you call the ControlTrace function to query the current session properties and then update those properties to update the session, make sure you set LogFileNameOffset to 0 (unless you are changing the log file name) and set EVENT_TRACE_PROPERTIES.Wnode.Flags to WNODE_FLAG_TRACED_GUID.

To obtain the property settings and session statistics for an event tracing session, call the ControlTrace function.

Examples

For an example that uses UpdateTrace, see Updating an Event Tracing Session.

Requirements

   
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header evntrace.h
Library Advapi32.lib
DLL Advapi32.dll

See Also

ControlTrace