Debug output
[Common]


Detailed Description

The debug output is implemented by instances of DebugStream which provides the following features:

The Dune-components should use the streams explained in Standard Debug Streams for output so that applications may redirect the output globally.

Changes in runtime are provided by three sets of methods:

The first methods implement a full stack whereas tie() is a bit different: though a tied stream may be (de)activated via push()/pop() you cannot attach() or detach() an output. You'll need to change the master stream instead.

Applications

Applications using the Dune-library should create an independent set of DebugStreams so that the debug levels can be changed separately. Example:

This code creates three streams of which only the last one really creates output. The output-routines of the other streams vanish in optimized executables.

You can use the common_bits-Template to switch to a policy using bitflags:

Applications that wish to redirect the Standard Debug Streams through their private streams may use the tie()-mechanism:

  // initialize streams like above

  Dune::dwarn.tie(coreout);

  // ... Dune-output to dwarn will be directed through coreout ...

  Dune::dwarn.untie();

Keep in mind to untie() a stream before the tied stream is destructed.

An alternative is to attach() an output stream defined by the application:

  std::ofstream mylog("application.log");

  Dune::dwarn.attach(mylog);

standard debug streams with level below MINIMAL_DEBUG_LEVEL will collapse to doing nothing if output is requested.

MINIMAL_DEBUG_LEVEL is set to DUNE_MINIMAL_DEBUG_LEVEL, wich is defined in config.h and can be changed by the configure option

 --with-minimal-debug-level=[grave|warn|info|verb|vverb] 

For a Dune-Release this should be set to at least 4 so that only important messages are active. Dune-developers may adapt this setting to their debugging needs locally

Keep in mind that libdune has to be recompiled if this value is changed!

The singleton instances of the available debug streams can befound in the Standard Debug Streams module


Files

file  debugstream.hh
file  stdstreams.hh

Modules

 Standard Debug Streams

Classes

struct  Dune::greater_or_equal< current, threshold >
 Greater or equal template test. More...
struct  Dune::notzero< x >
 Test if debug level equals zero. More...
struct  Dune::common_bits< current, mask >
 activate if current and mask have common bits switched on. More...
class  Dune::DebugStreamError
 standard exception for the debugstream More...
class  Dune::DebugStreamState
 Intermediate class to implement tie-operation of DebugStream. More...
class  Dune::DebugStream< thislevel, dlevel, alevel, activator >
 Generic class to implement debug output streams. More...

Typedefs

typedef unsigned int Dune::DebugLevel
 Type for debug levels.

Functions

 Dune::DebugStream::DebugStream (DebugStreamState &master, std::ostream &fallback=std::cerr)
 Create a DebugStream and directly tie to another DebugStream.
 Dune::DebugStream::~DebugStream ()
 Destroy stream.
template<class T>
DebugStream & Dune::DebugStream::operator<< (const T data)
 Generic types are passed on to current output stream.
DebugStream & Dune::DebugStream::operator<< (const int data)
 explicit specialization so that enums can be printed
DebugStream & Dune::DebugStream::operator<< (std::ostream &(*f)(std::ostream &))
 pass on manipulators to underlying output stream
DebugStream & Dune::DebugStream::flush ()
 pass on flush to underlying output stream
void Dune::DebugStream::push (bool b)
 set activation flag and store old value
void Dune::DebugStream::pop () throw (DebugStreamError)
 restore previously set activation flag
bool Dune::DebugStream::active () const
 reports if this stream will produce output
void Dune::DebugStream::attach (std::ostream &stream)
 set output to a different stream.
void Dune::DebugStream::detach () throw (DebugStreamError)
 detach current output stream and restore to previous stream
void Dune::DebugStream::untie () throw (DebugStreamError)
 Untie stream.

Variables

bool Dune::DebugStreamState::_active
 flag to switch output during runtime
bool Dune::DebugStreamState::_tied
 are we tied to another DebugStream?
unsigned int Dune::DebugStreamState::_tied_streams
 how many streams are tied to this state

Typedef Documentation

typedef unsigned int Dune::DebugLevel

Type for debug levels.

Only positive values allowed


Function Documentation

template<DebugLevel thislevel = 1, DebugLevel dlevel = 1, DebugLevel alevel = 1, template< DebugLevel, DebugLevel > class activator = greater_or_equal>
bool Dune::DebugStream< thislevel, dlevel, alevel, activator >::active (  )  const [inline, inherited]

reports if this stream will produce output

a DebugStream that is deactivated because of its level will always return false, otherwise the state of the internal activation is returned

template<DebugLevel thislevel = 1, DebugLevel dlevel = 1, DebugLevel alevel = 1, template< DebugLevel, DebugLevel > class activator = greater_or_equal>
void Dune::DebugStream< thislevel, dlevel, alevel, activator >::attach ( std::ostream &  stream  )  [inline, inherited]

set output to a different stream.

Old stream data is stored

template<DebugLevel thislevel = 1, DebugLevel dlevel = 1, DebugLevel alevel = 1, template< DebugLevel, DebugLevel > class activator = greater_or_equal>
Dune::DebugStream< thislevel, dlevel, alevel, activator >::DebugStream ( DebugStreamState master,
std::ostream &  fallback = std::cerr 
) [inline, inherited]

Create a DebugStream and directly tie to another DebugStream.

The fallback is used if a DebugStream constructed via this method is untie()ed later. Otherwise the stream would be broken afterwards.

template<DebugLevel thislevel = 1, DebugLevel dlevel = 1, DebugLevel alevel = 1, template< DebugLevel, DebugLevel > class activator = greater_or_equal>
DebugStream& Dune::DebugStream< thislevel, dlevel, alevel, activator >::operator<< ( const int  data  )  [inline, inherited]

explicit specialization so that enums can be printed

Operators for built-in types follow special rules (§11.2.3) so that enums won't fit into the generic method above. With an existing operator<< for int however the enum will be automatically casted.

template<DebugLevel thislevel = 1, DebugLevel dlevel = 1, DebugLevel alevel = 1, template< DebugLevel, DebugLevel > class activator = greater_or_equal>
Dune::DebugStream< thislevel, dlevel, alevel, activator >::~DebugStream (  )  [inline, inherited]

Destroy stream.

if other streams still tie() to this stream an exception will be thrown. Otherwise the child streams would certainly break on the next output

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