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TraceEvent()

Trace kernel events

Synopsis:

#include <sys/neutrino.h>

int TraceEvent( int mode, 
                ... );

Arguments:

mode: A command that indicates what you want to trace. Certain modes require additional arguments.

Library:

libc

Use the -l c option to qcc to link against this library. This library is usually included automatically.

Description:

The TraceEvent() function controls all stages of the instrumentation process such as initialization, starting, execution control and stopping. These stages consist of the following activities:

creating internal circular link list of trace buffers
initializing filters
turning on or off the event stream
deallocating the internal circular link list of trace buffers

This function requires the instrumented kernel. For more information, see the documentation for the System Analysis Toolkit (SAT).

Returns:

If mode is set to _NTO_TRACE_QUERYEVENTS: Number of events in the buffer, or -1 if an error occurs (errno is set).
If mode isn't set to _NTO_TRACE_QUERYEVENTS: 0 for success, or -1 if an error occurs (errno is set).

Errors:

ECANCELED: The requested action has been canceled.
EFAULT: The requested action has been specified out of order.
ENOMEM: Insufficient memory to allocate the trace buffers.
ENOSUP: The requested action isn't supported.
EPERM: The application doesn't have the appropriate permission to perform the action.

Classification:

QNX Neutrino

Safety:
Cancellation point	No
Interrupt handler	Read the Caveats
Signal handler	Yes
Thread	Yes

Caveats:

You can call TraceEvent() from an interrupt/event handler. However, not all trace modes are valid in this case. The valid trace modes are:

_NTO_TRACE_INSERTSUSEREVENT
_NTO_TRACE_INSERTCUSEREVENT
_NTO_TRACE_INSERTUSRSTREVENT
_NTO_TRACE_INSERTEVENT
_NTO_TRACE_STOP
_NTO_TRACE_STARTNOSTATE
_NTO_TRACE_START