Reference documentation for deal.II version GIT c9976103bc 2022-12-09 17:30:02+00:00
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Classes | Public Member Functions | Static Public Member Functions | Private Types | Private Member Functions | Private Attributes | Static Private Attributes | Friends | List of all members
LogStream Class Reference

#include <deal.II/base/logstream.h>

Inheritance diagram for LogStream:
[legend]

Classes

class  Prefix
 

Public Member Functions

 LogStream ()
 
 ~LogStream () override
 
void attach (std::ostream &o, const bool print_job_id=true, const std::ios_base::fmtflags flags=std::ios::showpoint|std::ios::left)
 
void detach ()
 
std::ostream & get_console ()
 
std::ostream & get_file_stream ()
 
bool has_file () const
 
const std::string & get_prefix () const
 
void push (const std::string &text)
 
void pop ()
 
unsigned int depth_console (const unsigned int n)
 
unsigned int depth_file (const unsigned int n)
 
bool log_thread_id (const bool flag)
 
std::streamsize precision (const std::streamsize prec)
 
std::streamsize width (const std::streamsize wide)
 
std::ios::fmtflags flags (const std::ios::fmtflags f)
 
LogStreamoperator<< (std::ostream &(*p)(std::ostream &))
 
std::size_t memory_consumption () const
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 
Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

void subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
 
void unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
 
unsigned int n_subscriptions () const
 
template<typename StreamType >
void list_subscribers (StreamType &stream) const
 
void list_subscribers () const
 

Static Public Member Functions

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 

Private Types

using map_value_type = decltype(counter_map)::value_type
 
using map_iterator = decltype(counter_map)::iterator
 

Private Member Functions

std::stack< std::string > & get_prefixes () const
 
void print_line_head ()
 
std::ostringstream & get_stream ()
 
void check_no_subscribers () const noexcept
 

Private Attributes

Threads::ThreadLocalStorage< std::stack< std::string > > prefixes
 
std::thread::id parent_thread
 
std::ostream * std_out
 
std::ostream * file
 
unsigned int std_depth
 
unsigned int file_depth
 
bool print_thread_id
 
bool at_newline
 
Threads::ThreadLocalStorage< std::shared_ptr< std::ostringstream > > outstreams
 
std::atomic< unsigned int > counter
 
std::map< std::string, unsigned int > counter_map
 
std::vector< std::atomic< bool > * > validity_pointers
 
const std::type_info * object_info
 

Static Private Attributes

static std::mutex mutex
 

Friends

template<typename T >
LogStreamoperator<< (LogStream &log, const T &t)
 

Detailed Description

A class that simplifies the process of execution logging. It does so by providing

The usual usage of this class is through the pregenerated object deallog. Typical setup steps are:

Before entering a new phase of your program, e.g. a new loop, a new prefix can be set via LogStream::Prefix p("loopname");. The destructor of the prefix will pop the prefix text from the stack.

Write via the << operator, deallog << "This is a log notice"; will be buffered thread locally until a std::flush or std::endl is encountered, which will trigger a writeout to the console and, if set up, the log file.

LogStream and thread safety

In the vicinity of concurrent threads, LogStream behaves in the following manner:

Definition at line 81 of file logstream.h.

Member Typedef Documentation

◆ map_value_type

using Subscriptor::map_value_type = decltype(counter_map)::value_type
privateinherited

The data type used in counter_map.

Definition at line 230 of file subscriptor.h.

◆ map_iterator

using Subscriptor::map_iterator = decltype(counter_map)::iterator
privateinherited

The iterator type used in counter_map.

Definition at line 235 of file subscriptor.h.

Constructor & Destructor Documentation

◆ LogStream()

LogStream::LogStream ( )

Standard constructor. The constructor sets the output stream to std::cout and the depth to zero. (Use attach() and depth_console() to change this.)

Definition at line 75 of file logstream.cc.

◆ ~LogStream()

LogStream::~LogStream ( )
override

Destructor.

Definition at line 89 of file logstream.cc.

Member Function Documentation

◆ attach()

void LogStream::attach ( std::ostream &  o,
const bool  print_job_id = true,
const std::ios_base::fmtflags  flags = std::ios::showpoint | std::ios::left 
)

Enable output to a second stream o.

Parameters
oAttach this output stream.
[in]print_job_idWhether or not the JobIdentifier for the current process should be printed to the stream.
[in]flagsFormat flags to set on the output stream o.

Definition at line 219 of file logstream.cc.

◆ detach()

void LogStream::detach ( )

Disable output to the second stream. You may want to call close on the stream that was previously attached to this object.

Definition at line 232 of file logstream.cc.

◆ get_console()

std::ostream & LogStream::get_console ( )

Return the default stream (std_out).

Definition at line 240 of file logstream.cc.

◆ get_file_stream()

std::ostream & LogStream::get_file_stream ( )

Return the file stream.

Definition at line 271 of file logstream.cc.

◆ has_file()

bool LogStream::has_file ( ) const

Return true if file stream has already been attached, false otherwise.

Definition at line 282 of file logstream.cc.

◆ get_prefix()

const std::string & LogStream::get_prefix ( ) const

Return the prefix string.

Definition at line 290 of file logstream.cc.

◆ push()

void LogStream::push ( const std::string &  text)

Push another prefix on the stack. Prefixes are automatically separated by a colon and there is a double colon after the last prefix.

A simpler way to add a prefix (without the manual need to add the corresponding pop()) is to use the LogStream::Prefix class. Using that class has the advantage that the corresponding pop() call is issued whenever the Prefix object goes out of scope – either at the end of the code block, at the nearest return statement, or because an intermediate function call results in an exception that is not immediately caught.

Definition at line 303 of file logstream.cc.

◆ pop()

void LogStream::pop ( )

Remove the last prefix added with push().

Definition at line 317 of file logstream.cc.

◆ depth_console()

unsigned int LogStream::depth_console ( const unsigned int  n)

Maximum number of levels to be printed on the console. The default is 0, which will not generate any output. This function allows one to restrict console output to the highest levels of iterations. Only output with less than n prefixes is printed. By calling this function with n=0, no console output will be written. See step-3 for an example usage of this method.

The previous value of this parameter is returned.

Definition at line 350 of file logstream.cc.

◆ depth_file()

unsigned int LogStream::depth_file ( const unsigned int  n)

Maximum number of levels to be written to the log file. The functionality is the same as depth_console, nevertheless, this function should be used with care, since it may spoil the value of a log file.

The previous value of this parameter is returned.

Definition at line 361 of file logstream.cc.

◆ log_thread_id()

bool LogStream::log_thread_id ( const bool  flag)

Log the thread id.

Definition at line 372 of file logstream.cc.

◆ precision()

std::streamsize LogStream::precision ( const std::streamsize  prec)

set the precision for the underlying stream and returns the previous stream precision. This function mimics http://www.cplusplus.com/reference/ios/ios_base/precision/

Definition at line 334 of file logstream.cc.

◆ width()

std::streamsize LogStream::width ( const std::streamsize  wide)

set the width for the underlying stream and returns the previous stream width. This function mimics http://www.cplusplus.com/reference/ios/ios_base/width/

Definition at line 342 of file logstream.cc.

◆ flags()

std::ios::fmtflags LogStream::flags ( const std::ios::fmtflags  f)

set the flags for the underlying stream and returns the previous stream flags. This function mimics http://www.cplusplus.com/reference/ios/ios_base/flags/

Definition at line 326 of file logstream.cc.

◆ operator<<()

LogStream & LogStream::operator<< ( std::ostream &(*)(std::ostream &)  p)

Treat ostream manipulators. This passes on the whole thing to the template function with the exception of the std::endl manipulator, for which special action is performed: write the temporary stream buffer including a header to the file and std::cout and empty the buffer.

An overload of this function is needed anyway, since the compiler can't bind manipulators like std::endl directly to template arguments T like in the previous general template. This is due to the fact that std::endl is actually an overloaded set of functions for std::ostream, std::wostream, and potentially more of this kind. This function is therefore necessary to pick one element from this overload set.

Definition at line 125 of file logstream.cc.

◆ memory_consumption()

std::size_t LogStream::memory_consumption ( ) const

Return an estimate for the memory consumption, in bytes, of this object. This is not exact (but will usually be close) because calculating the memory usage of trees (e.g., std::map) is difficult.

◆ get_prefixes()

std::stack< std::string > & LogStream::get_prefixes ( ) const
private

Internal wrapper around thread-local prefixes. This private function will return the correct internal prefix stack. More important, a new thread- local stack will be copied from the current stack of the "blessed" thread that created this LogStream instance (usually, in the case of deallog, the "main" thread).

Definition at line 383 of file logstream.cc.

◆ print_line_head()

void LogStream::print_line_head ( )
private

Print head of line.

Definition at line 403 of file logstream.cc.

◆ get_stream()

std::ostringstream & LogStream::get_stream ( )
private

Internal wrapper around "thread local" outstreams. This private function will return the correct internal ostringstream buffer for operator<<.

Definition at line 248 of file logstream.cc.

◆ subscribe()

void Subscriptor::subscribe ( std::atomic< bool > *const  validity,
const std::string &  identifier = "" 
) const
inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

◆ unsubscribe()

void Subscriptor::unsubscribe ( std::atomic< bool > *const  validity,
const std::string &  identifier = "" 
) const
inherited

Unsubscribes a user from the object.

Note
The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

◆ n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const
inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

◆ list_subscribers() [1/2]

template<typename StreamType >
void Subscriptor::list_subscribers ( StreamType &  stream) const
inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

◆ serialize()

template<class Archive >
void Subscriptor::serialize ( Archive &  ar,
const unsigned int  version 
)
inlineinherited

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

◆ check_no_subscribers()

void Subscriptor::check_no_subscribers ( ) const
privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note
Since this function is just a consistency check it does nothing in release mode.
If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 53 of file subscriptor.cc.

Friends And Related Function Documentation

◆ operator<<

template<typename T >
LogStream& operator<< ( LogStream log,
const T &  t 
)
friend

Output a constant something through LogStream:

Note
We declare this operator as a non-member function so that it is possible to overload it with more specialized templated versions under C++11 overload resolution rules

Definition at line 405 of file logstream.h.

Member Data Documentation

◆ prefixes

Threads::ThreadLocalStorage<std::stack<std::string> > LogStream::prefixes
mutableprivate

Stack of strings which are printed at the beginning of each line to allow identification where the output was generated.

Definition at line 321 of file logstream.h.

◆ parent_thread

std::thread::id LogStream::parent_thread
private

We record the thread id of the thread creating this object. We need this information to "steal" the current prefix from this "parent" thread on first use of deallog on a new thread.

Definition at line 328 of file logstream.h.

◆ std_out

std::ostream* LogStream::std_out
private

Default stream, where the output is to go to. This stream defaults to std::cout, but can be set to another stream through the constructor.

Definition at line 335 of file logstream.h.

◆ file

std::ostream* LogStream::file
private

Pointer to a stream, where a copy of the output is to go to. Usually, this will be a file stream.

You can set and reset this stream by the attach function.

Definition at line 343 of file logstream.h.

◆ std_depth

unsigned int LogStream::std_depth
private

Value denoting the number of prefixes to be printed to the standard output. If more than this number of prefixes is pushed to the stack, then no output will be generated until the number of prefixes shrinks back below this number.

Definition at line 351 of file logstream.h.

◆ file_depth

unsigned int LogStream::file_depth
private

Same for the maximum depth of prefixes for output to a file.

Definition at line 356 of file logstream.h.

◆ print_thread_id

bool LogStream::print_thread_id
private

Flag for printing thread id.

Definition at line 361 of file logstream.h.

◆ at_newline

bool LogStream::at_newline
private

A flag indicating whether output is currently at a new line

Definition at line 366 of file logstream.h.

◆ outstreams

Threads::ThreadLocalStorage<std::shared_ptr<std::ostringstream> > LogStream::outstreams
private

We use our thread local storage facility to generate a stringstream for every thread that sends log messages.

Definition at line 385 of file logstream.h.

◆ counter

std::atomic<unsigned int> Subscriptor::counter
mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 219 of file subscriptor.h.

◆ counter_map

std::map<std::string, unsigned int> Subscriptor::counter_map
mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 225 of file subscriptor.h.

◆ validity_pointers

std::vector<std::atomic<bool> *> Subscriptor::validity_pointers
mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 241 of file subscriptor.h.

◆ object_info

const std::type_info* Subscriptor::object_info
mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 249 of file subscriptor.h.

◆ mutex

std::mutex Subscriptor::mutex
staticprivateinherited

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.


The documentation for this class was generated from the following files: