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

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

See also:

InterruptAttach(), InterruptHookTrace()