RWTraceLevelFilter

Threads Module Reference Guide
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RWTraceLevelFilter

Module: Threads Package: Execution Tracing


RWTraceLevelFilter   RWTraceSingleClientfilter   
   RWTraceEventFilter......   RWTraceEventClient

Local Index
Header File
Description
Example
Public Constructors
Public Destructor
Public Member Functions

Local Index

Members

getLevel()

RWTraceLevelFilter()

setLevel()

~RWTraceLevelFilter()

Header File

#include <rw/trace/RWTraceLevelFilter.h>

Description

RWTraceLevelFilter is a single-client filter that lets only events of the supplied severity level or higher pass through.

Example

#define RW_USER_TRACE_LEVEL 8                               //1

#include <rw/trace/trace.h>

int main() 
{
  RWTraceOstreamClient myTraceClient(cerr);                 //2

  // create filter that only lets INFO and more important events
  // pass through
  RWTraceLevelFilter myTraceLevelFilter(RW_TRACE_LEVEL_INFO);//3

  // connect client to level filter
  myTraceClient.connect(myTraceLevelFilter);                //4

  // connect level filter to manager
  myTraceLevelFilter.connectToManager();                    //5

  RW_USER_TRACEABLE_FUNCTION("main");                       //6

  // generate some trace information
  RW_USER_TRACE_INFO("This info level message should be seen.");
 
  // change the level
  myTraceLevelFilter.setLevel(RW_TRACE_LEVEL_ERROR);        //7

  // generate some more trace information
  RW_USER_TRACE_INFO("This info level message should not be
                                                     seen.");
  RW_USER_TRACE_ERROR("This error level message should be
                                                    seen.");

  return 0;
}

The following is a description of each program line:

`//1`	Compile in all trace macros by setting the user trace level macro to 8. This line sets the maximum trace level to compile into the code. To compile in all the trace macros, the level is set to the maximum 8 (Entry/Exit). You could also define the trace level on the command line for your compiler, using the flag `-DRW_USER_TRACE_LEVEL=8`.
`//2`	Create a normal *std::ostream* client to display the trace information.
`//3`	Instantiate an *RWTraceLevelFilter. The constructor takes the maximum level of trace messages to pass through. You can pass an integer level number (see Section 6.1.3 of the Threads Module User's Guide*) or use one of the symbolic constants, as in this line. Pass 0 to filter out all trace messages.
`//4`	Connect the client to the level filter.
`//5`	Then connect the filter to the trace manager.
`//6`	Declare the function as traceable, so you can use trace event generation macros in this function.
`//7`	Change the cutoff level on the level filter, using the `setLevel()` function.

The symbolic constants referred to in line //3 are defined in the file
rw/trace/RWTraceEventSeverity.h. They cannot be used when setting the RW_USER_TRACE_LEVEL macro, because this macro needs to be set before including any trace header files. They include:

RW_TRACE_LEVEL_FATAL
RW_TRACE_LEVEL_ERROR
RW_TRACE_LEVEL_WARNING
RW_TRACE_LEVEL_INFO
RW_TRACE_LEVEL_TEST
RW_TRACE_LEVEL_DEBUG
RW_TRACE_LEVEL_ENTRY
RW_TRACE_LEVEL_NONE

All of these constants map directly to the appropriate severity level. RW_TRACE_LEVEL_NONE filters out all trace messages. It is equivalent to zero.

Public Constructors

RWTraceLevelFilter(RWStaticCtor);

Constructs a global static handle instance (may be used before being constructed).

RWTraceLevelFilter(RWTraceEventSeverity level = RW_TRACE_LEVEL_NONE);

Default constructor. If no level is supplied, the default is RW_TRACE_LEVEL_NONE. In this case, no events are passed on.

RWTraceLevelFilter(RWTraceLevelFilterImp* bodyP);

Attaches to and increments the reference count on a body.

RWTraceLevelFilter(const RWTraceLevelFilter& second);

Copy constructor.

Public Destructor

~RWTraceLevelFilter();

Destructor.

Public Member Functions

RWTraceEventSeverity 
getLevel() const;

Returns the filter's severity level.

void 
setLevel(const RWTraceEventSeverity level);

Sets the severity level for the filter.

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