Reference documentation for deal.II version 9.1.1
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Classes | Public Member Functions | Private Member Functions | 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
 
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 
 Subscriptor (const Subscriptor &)
 
 Subscriptor (Subscriptor &&) noexcept
 
virtual ~Subscriptor ()
 
Subscriptoroperator= (const Subscriptor &)
 
Subscriptoroperator= (Subscriptor &&) noexcept
 
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
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 

Private Member Functions

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

Private Attributes

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

Friends

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

Additional Inherited Members

- Static Public Member Functions inherited from Subscriptor
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 

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:

Author
Guido Kanschat, Wolfgang Bangerth, 1999, 2003, 2011

Definition at line 83 of file logstream.h.

Constructor & Destructor Documentation

◆ LogStream()

LogStream::LogStream ( )

Standard constructor. The standard output stream to std::cout.

Definition at line 75 of file logstream.cc.

◆ ~LogStream()

LogStream::~LogStream ( )
override

Destructor.

Definition at line 88 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 218 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 231 of file logstream.cc.

◆ get_console()

std::ostream & LogStream::get_console ( )

Return the default stream (std_out).

Definition at line 239 of file logstream.cc.

◆ get_file_stream()

std::ostream & LogStream::get_file_stream ( )

Return the file stream.

Definition at line 270 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 281 of file logstream.cc.

◆ get_prefix()

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

Return the prefix string.

Definition at line 289 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 302 of file logstream.cc.

◆ pop()

void LogStream::pop ( )

Remove the last prefix added with push().

Definition at line 316 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 349 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 360 of file logstream.cc.

◆ log_thread_id()

bool LogStream::log_thread_id ( const bool  flag)

Log the thread id.

Definition at line 371 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 333 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 341 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 325 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 382 of file logstream.cc.

◆ print_line_head()

void LogStream::print_line_head ( )
private

Print head of line.

Definition at line 416 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 247 of file logstream.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 400 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 322 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 329 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 337 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 345 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 350 of file logstream.h.

◆ print_thread_id

bool LogStream::print_thread_id
private

Flag for printing thread id.

Definition at line 355 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 360 of file logstream.h.

◆ outstreams

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

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

Definition at line 379 of file logstream.h.


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