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std.experimental.logger.core

template isLoggingActiveAt(LogLevel ll)
This template evaluates if the passed LogLevel is active. The previously described version statements are used to decide if the LogLevel is active. The version statements only influence the compile unit they are used with, therefore this function can only disable logging this specific compile unit.
enum bool isLoggingActive;
This compile-time flag is true if logging is not statically disabled.
@safe bool isLoggingEnabled()(LogLevel ll, LogLevel loggerLL, LogLevel globalLL, lazy bool condition = true);
This functions is used at runtime to determine if a LogLevel is active. The same previously defined version statements are used to disable certain levels. Again the version statements are associated with a compile unit and can therefore not disable logging in other compile units. pure bool isLoggingEnabled()(LogLevel ll) @safe nothrow @nogc
template moduleLogLevel(string moduleName) if (!moduleName.length)

template moduleLogLevel(string moduleName) if (moduleName.length)
This template returns the LogLevel named "logLevel" of type LogLevel defined in a user defined module where the filename has the suffix "loggerconfig.d". This LogLevel sets the minimal LogLevel of the module.
A minimal LogLevel can be defined on a per module basis. In order to define a module LogLevel a file with a modulename "MODULENAME_loggerconfig" must be found. If no such module exists and the module is a nested module, it is checked if there exists a "PARENT_MODULE_loggerconfig" module with such a symbol. If this module exists and it contains a LogLevel called logLevel this LogLevel will be used. This parent lookup is continued until there is no parent module. Then the moduleLogLevel is LogLevel.all.
Examples: 
static assert(moduleLogLevel!"" == LogLevel.all);
Examples: 
static assert(moduleLogLevel!"not.amodule.path" == LogLevel.all);
void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy bool condition, lazy A args)
if (args.length != 1);

void log(T, string moduleName = __MODULE__)(const LogLevel ll, lazy bool condition, lazy T arg, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__);
This function logs data.
In order for the data to be processed, the LogLevel of the log call must be greater or equal to the LogLevel of the sharedLog and the defaultLogLevel; additionally the condition passed must be true.
Parameters:
LogLevel ll The LogLevel used by this log call.
bool condition The condition must be true for the data to be logged.
A args The data that should be logged.

Example 

log(LogLevel.warning, true, "Hello World", 3.1415);

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy A args)
if (args.length > 1 && !is(Unqual!(A[0]) : bool));

void log(T, string moduleName = __MODULE__)(const LogLevel ll, lazy T arg, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__);
This function logs data.
In order for the data to be processed the LogLevel of the log call must be greater or equal to the LogLevel of the sharedLog.
Parameters:
LogLevel ll The LogLevel used by this log call.
A args The data that should be logged.

Example 

log(LogLevel.warning, "Hello World", 3.1415);

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy A args)
if (args.length != 1);

void log(T, string moduleName = __MODULE__)(lazy bool condition, lazy T arg, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__);
This function logs data.
In order for the data to be processed the LogLevel of the sharedLog must be greater or equal to the defaultLogLevel add the condition passed must be true.
Parameters:
bool condition The condition must be true for the data to be logged.
A args The data that should be logged.

Example 

log(true, "Hello World", 3.1415);

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args)
if (args.length > 1 && !is(Unqual!(A[0]) : bool) && !is(Unqual!(A[0]) == LogLevel) || args.length == 0);
This function logs data.
In order for the data to be processed the LogLevel of the sharedLog must be greater or equal to the defaultLogLevel.
Parameters:
A args The data that should be logged.

Example 

log("Hello World", 3.1415);

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy bool condition, lazy string msg, lazy A args);
This function logs data in a printf-style manner.
In order for the data to be processed the LogLevel of the log call must be greater or equal to the LogLevel of the sharedLog and the defaultLogLevel additionally the condition passed must be true.
Parameters:
LogLevel ll The LogLevel used by this log call.
bool condition The condition must be true for the data to be logged.
string msg The printf-style string.
A args The data that should be logged.

Example 

logf(LogLevel.warning, true, "Hello World %f", 3.1415);

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy string msg, lazy A args);
This function logs data in a printf-style manner.
In order for the data to be processed the LogLevel of the log call must be greater or equal to the LogLevel of the sharedLog and the defaultLogLevel.
Parameters:
LogLevel ll The LogLevel used by this log call.
string msg The printf-style string.
A args The data that should be logged.

Example 

logf(LogLevel.warning, "Hello World %f", 3.1415);

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);
This function logs data in a printf-style manner.
In order for the data to be processed the LogLevel of the log call must be greater or equal to the defaultLogLevel additionally the condition passed must be true.
Parameters:
bool condition The condition must be true for the data to be logged.
string msg The printf-style string.
A args The data that should be logged.

Example 

logf(true, "Hello World %f", 3.1415);

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);
This function logs data in a printf-style manner.
In order for the data to be processed the LogLevel of the log call must be greater or equal to the defaultLogLevel.
Parameters:
string msg The printf-style string.
A args The data that should be logged.

Example 

logf("Hello World %f", 3.1415);

template defaultLogFunction(LogLevel ll)
This template provides the global log functions with the LogLevel is encoded in the function name.
The aliases following this template create the public names of these log functions.
alias trace = defaultLogFunction!cast(LogLevel)cast(ubyte)32u.defaultLogFunction(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length > 0 && !is(Unqual!(A[0]) : bool) || args.length == 0);

alias info = defaultLogFunction!cast(LogLevel)cast(ubyte)64u.defaultLogFunction(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length > 0 && !is(Unqual!(A[0]) : bool) || args.length == 0);

alias warning = defaultLogFunction!cast(LogLevel)cast(ubyte)96u.defaultLogFunction(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length > 0 && !is(Unqual!(A[0]) : bool) || args.length == 0);

alias error = defaultLogFunction!cast(LogLevel)cast(ubyte)128u.defaultLogFunction(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length > 0 && !is(Unqual!(A[0]) : bool) || args.length == 0);

alias critical = defaultLogFunction!cast(LogLevel)cast(ubyte)160u.defaultLogFunction(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length > 0 && !is(Unqual!(A[0]) : bool) || args.length == 0);

alias fatal = defaultLogFunction!cast(LogLevel)cast(ubyte)192u.defaultLogFunction(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length > 0 && !is(Unqual!(A[0]) : bool) || args.length == 0);
This function logs data to the stdThreadLocalLog, optionally depending on a condition.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the stdThreadLocalLog and must be greater or equal than the global LogLevel. Additionally the LogLevel must be greater or equal than the LogLevel of the stdSharedLogger. If a condition is given, it must evaluate to true.
Parameters:
bool condition The condition must be true for the data to be logged.
A args The data that should be logged.

Example 

trace(1337, "is number");
info(1337, "is number");
error(1337, "is number");
critical(1337, "is number");
fatal(1337, "is number");
trace(true, 1337, "is number");
info(false, 1337, "is number");
error(true, 1337, "is number");
critical(false, 1337, "is number");
fatal(true, 1337, "is number");

template defaultLogFunctionf(LogLevel ll)
This template provides the global printf-style log functions with the LogLevel is encoded in the function name.
The aliases following this template create the public names of the log functions.
alias tracef = defaultLogFunctionf!cast(LogLevel)cast(ubyte)32u.defaultLogFunctionf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);

alias infof = defaultLogFunctionf!cast(LogLevel)cast(ubyte)64u.defaultLogFunctionf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);

alias warningf = defaultLogFunctionf!cast(LogLevel)cast(ubyte)96u.defaultLogFunctionf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);

alias errorf = defaultLogFunctionf!cast(LogLevel)cast(ubyte)128u.defaultLogFunctionf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);

alias criticalf = defaultLogFunctionf!cast(LogLevel)cast(ubyte)160u.defaultLogFunctionf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);

alias fatalf = defaultLogFunctionf!cast(LogLevel)cast(ubyte)192u.defaultLogFunctionf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);
This function logs data to the sharedLog in a printf-style manner.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the sharedLog and must be greater or equal than the global LogLevel. Additionally the LogLevel must be greater or equal than the LogLevel of the stdSharedLogger.
Parameters:
string msg The printf-style string.
A args The data that should be logged.

Example 

tracef("is number %d", 1);
infof("is number %d", 2);
errorf("is number %d", 3);
criticalf("is number %d", 4);
fatalf("is number %d", 5);
The second version of the function logs data to the sharedLog in a printf-style manner.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the sharedLog and must be greater or equal than the global LogLevel. Additionally the LogLevel must be greater or equal than the LogLevel of the stdSharedLogger.

Parameters:
bool condition The condition must be true for the data to be logged.
string msg The printf-style string.
A args The data that should be logged.

Example 

tracef(false, "is number %d", 1);
infof(false, "is number %d", 2);
errorf(true, "is number %d", 3);
criticalf(true, "is number %d", 4);
fatalf(someFunct(), "is number %d", 5);

enum LogLevel: ubyte;
There are eight usable logging level. These level are all, trace, info, warning, error, critical, fatal, and off. If a log function with LogLevel.fatal is called the shutdown handler of that logger is called.
all
Lowest possible assignable LogLevel.
trace
LogLevel for tracing the execution of the program.
info
This level is used to display information about the program.
warning
warnings about the program should be displayed with this level.
error
Information about errors should be logged with this level.
critical
Messages that inform about critical errors should be logged with this level.
fatal
Log messages that describe fatal errors should use this level.
off
Highest possible LogLevel.
abstract class Logger;
This class is the base of every logger. In order to create a new kind of logger a deriving class needs to implement the writeLogMsg method. By default this is not thread-safe.
It is also possible to override the three methods beginLogMsg, logMsgPart and finishLogMsg together, this option gives more flexibility.
struct LogEntry;
LogEntry is a aggregation combining all information associated with a log message. This aggregation will be passed to the method writeLogMsg.
string file;
the filename the log function was called from
int line;
the line number the log function was called from
string funcName;
the name of the function the log function was called from
string prettyFuncName;
the pretty formatted name of the function the log function was called from
string moduleName;
the name of the module the log message is coming from
LogLevel logLevel;
the LogLevel associated with the log message
Tid threadId;
thread id of the log message
SysTime timestamp;
the time the message was logged
string msg;
the message of the log message
Logger logger;
A refernce to the Logger used to create this LogEntry
@safe this(LogLevel lv);
Every subclass of Logger has to call this constructor from their constructor. It sets the LogLevel, and creates a fatal handler. The fatal handler will throw an Error if a log call is made with level LogLevel.fatal.
Parameters:
LogLevel lv LogLevel to use for this Logger instance.
protected abstract @safe void writeLogMsg(ref LogEntry payload);
A custom logger must implement this method in order to work in a MultiLogger and ArrayLogger.
Parameters:
LogEntry payload All information associated with call to log function.
See Also:
beginLogMsg, logMsgPart, finishLogMsg
protected @safe void logMsgPart(const(char)[] msg);
Logs a part of the log message.
protected @safe void finishLogMsg();
Signals that the message has been written and no more calls to logMsgPart follow.
final const pure @nogc @property @safe LogLevel logLevel();

final @nogc @property @safe void logLevel(const LogLevel lv);
The LogLevel determines if the log call are processed or dropped by the Logger. In order for the log call to be processed the LogLevel of the log call must be greater or equal to the LogLevel of the logger.
These two methods set and get the LogLevel of the used Logger.

Example 

auto f = new FileLogger(stdout);
f.logLevel = LogLevel.info;
assert(f.logLevel == LogLevel.info);

final @nogc @property @safe void delegate() fatalHandler();

final @nogc @property @safe void fatalHandler(void delegate() @safe fh);
This delegate is called in case a log message with LogLevel.fatal gets logged.
By default an Error will be thrown.
@trusted void forwardMsg(ref LogEntry payload);
This method allows forwarding log entries from one logger to another.
forwardMsg will ensure proper synchronization and then call writeLogMsg. This is an API for implementing your own loggers and should not be called by normal user code. A notable difference from other logging functions is that the globalLogLevel wont be evaluated again since it is assumed that the caller already checked that.
template memLogFunctions(LogLevel ll)

alias trace = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)32u.logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length == 0 || args.length > 0 && !is(A[0] : bool));

alias tracef = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)32u.logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);

alias info = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)64u.logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length == 0 || args.length > 0 && !is(A[0] : bool));

alias infof = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)64u.logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);

alias warning = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)96u.logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length == 0 || args.length > 0 && !is(A[0] : bool));

alias warningf = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)96u.logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);

alias error = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)128u.logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length == 0 || args.length > 0 && !is(A[0] : bool));

alias errorf = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)128u.logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);

alias critical = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)160u.logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length == 0 || args.length > 0 && !is(A[0] : bool));

alias criticalf = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)160u.logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);

alias fatal = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)192u.logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args) if (args.length == 0 || args.length > 0 && !is(A[0] : bool));

alias fatalf = .Logger.memLogFunctions!cast(LogLevel)cast(ubyte)192u.logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);
This template provides the log functions for the Logger class with the LogLevel encoded in the function name.
For further information see the the two functions defined inside of this template.
The aliases following this template create the public names of these log functions.
void logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args)
if (args.length == 0 || args.length > 0 && !is(A[0] : bool));
This function logs data to the used Logger.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel.
Parameters:
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.trace(1337, "is number");
s.info(1337, "is number");
s.error(1337, "is number");
s.critical(1337, "is number");
s.fatal(1337, "is number");

void logImpl(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy A args);
This function logs data to the used Logger depending on a condition.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel additionally the condition passed must be true.
Parameters:
bool condition The condition must be true for the data to be logged.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.trace(true, 1337, "is number");
s.info(false, 1337, "is number");
s.error(true, 1337, "is number");
s.critical(false, 1337, "is number");
s.fatal(true, 1337, "is number");

void logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);
This function logs data to the used Logger in a printf-style manner.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel additionally the passed condition must be true.
Parameters:
bool condition The condition must be true for the data to be logged.
string msg The printf-style string.
A args The data that should be logged.

Example 

auto s = new FileLogger(stderr);
s.tracef(true, "is number %d", 1);
s.infof(true, "is number %d", 2);
s.errorf(false, "is number %d", 3);
s.criticalf(someFunc(), "is number %d", 4);
s.fatalf(true, "is number %d", 5);

void logImplf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);
This function logs data to the used Logger in a printf-style manner.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel.
Parameters:
string msg The printf-style string.
A args The data that should be logged.

Example 

auto s = new FileLogger(stderr);
s.tracef("is number %d", 1);
s.infof("is number %d", 2);
s.errorf("is number %d", 3);
s.criticalf("is number %d", 4);
s.fatalf("is number %d", 5);

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy bool condition, lazy A args)
if (args.length != 1);

void log(T, string moduleName = __MODULE__)(const LogLevel ll, lazy bool condition, lazy T args, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__);
This method logs data with the LogLevel of the used Logger.
This method takes a bool as first argument. In order for the data to be processed the bool must be true and the LogLevel of the Logger must be greater or equal to the global LogLevel.
Parameters:
A args The data that should be logged.
bool condition The condition must be true for the data to be logged.
A args The data that is to be logged.
Returns:
The logger used by the logging function as reference.

Example 

auto l = new StdioLogger();
l.log(1337);

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy A args)
if (args.length > 1 && !is(Unqual!(A[0]) : bool) || args.length == 0);

void log(T)(const LogLevel ll, lazy T args, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__);
This function logs data to the used Logger with a specific LogLevel.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel.
Parameters:
LogLevel ll The specific LogLevel used for logging the log message.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.log(LogLevel.trace, 1337, "is number");
s.log(LogLevel.info, 1337, "is number");
s.log(LogLevel.warning, 1337, "is number");
s.log(LogLevel.error, 1337, "is number");
s.log(LogLevel.fatal, 1337, "is number");

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy A args)
if (args.length != 1);

void log(T)(lazy bool condition, lazy T args, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__);
This function logs data to the used Logger depending on a explicitly passed condition with the LogLevel of the used Logger.
In order for the resulting log message to be logged the LogLevel of the used Logger must be greater or equal than the global LogLevel and the condition must be true.
Parameters:
bool condition The condition must be true for the data to be logged.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.log(true, 1337, "is number");
s.log(true, 1337, "is number");
s.log(true, 1337, "is number");
s.log(false, 1337, "is number");
s.log(false, 1337, "is number");

void log(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy A args)
if (args.length > 1 && !is(Unqual!(A[0]) : bool) && !is(Unqual!(A[0]) == LogLevel) || args.length == 0);

void log(T)(lazy T arg, int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__);
This function logs data to the used Logger with the LogLevel of the used Logger.
In order for the resulting log message to be logged the LogLevel of the used Logger must be greater or equal than the global LogLevel.
Parameters:
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.log(1337, "is number");
s.log(info, 1337, "is number");
s.log(1337, "is number");
s.log(1337, "is number");
s.log(1337, "is number");

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy bool condition, lazy string msg, lazy A args);
This function logs data to the used Logger with a specific LogLevel and depending on a condition in a printf-style manner.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel and the condition must be true.
Parameters:
LogLevel ll The specific LogLevel used for logging the log message.
bool condition The condition must be true for the data to be logged.
string msg The format string used for this log call.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.logf(LogLevel.trace, true ,"%d %s", 1337, "is number");
s.logf(LogLevel.info, true ,"%d %s", 1337, "is number");
s.logf(LogLevel.warning, true ,"%d %s", 1337, "is number");
s.logf(LogLevel.error, false ,"%d %s", 1337, "is number");
s.logf(LogLevel.fatal, true ,"%d %s", 1337, "is number");

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(const LogLevel ll, lazy string msg, lazy A args);
This function logs data to the used Logger with a specific LogLevel in a printf-style manner.
In order for the resulting log message to be logged the LogLevel must be greater or equal than the LogLevel of the used Logger and must be greater or equal than the global LogLevel.
Parameters:
LogLevel ll The specific LogLevel used for logging the log message.
string msg The format string used for this log call.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.logf(LogLevel.trace, "%d %s", 1337, "is number");
s.logf(LogLevel.info, "%d %s", 1337, "is number");
s.logf(LogLevel.warning, "%d %s", 1337, "is number");
s.logf(LogLevel.error, "%d %s", 1337, "is number");
s.logf(LogLevel.fatal, "%d %s", 1337, "is number");

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy bool condition, lazy string msg, lazy A args);
This function logs data to the used Logger depending on a condition with the LogLevel of the used Logger in a printf-style manner.
In order for the resulting log message to be logged the LogLevel of the used Logger must be greater or equal than the global LogLevel and the condition must be true.
Parameters:
bool condition The condition must be true for the data to be logged.
string msg The format string used for this log call.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.logf(true ,"%d %s", 1337, "is number");
s.logf(true ,"%d %s", 1337, "is number");
s.logf(true ,"%d %s", 1337, "is number");
s.logf(false ,"%d %s", 1337, "is number");
s.logf(true ,"%d %s", 1337, "is number");

void logf(int line = __LINE__, string file = __FILE__, string funcName = __FUNCTION__, string prettyFuncName = __PRETTY_FUNCTION__, string moduleName = __MODULE__, A...)(lazy string msg, lazy A args);
This method logs data to the used Logger with the LogLevel of the this Logger in a printf-style manner.
In order for the data to be processed the LogLevel of the Logger must be greater or equal to the global LogLevel.
Parameters:
string msg The format string used for this log call.
A args The data that should be logged.

Example 

auto s = new FileLogger(stdout);
s.logf("%d %s", 1337, "is number");
s.logf("%d %s", 1337, "is number");
s.logf("%d %s", 1337, "is number");
s.logf("%d %s", 1337, "is number");
s.logf("%d %s", 1337, "is number");

@property @safe Logger sharedLog();

@property @trusted void sharedLog(Logger logger);
This property sets and gets the default Logger.

Example 

sharedLog = new FileLogger(yourFile);
The example sets a new FileLogger as new sharedLog.
If at some point you want to use the original default logger again, you can use sharedLog = null;. This will put back the original.

Note While getting and setting sharedLog is thread-safe, it has to be considered that the returned reference is only a current snapshot and in the following code, you must make sure no other thread reassigns to it between reading and writing sharedLog.

sharedLog is only thread-safe if the the used Logger is thread-safe. The default Logger is thread-safe. 
if (sharedLog !is myLogger)
    sharedLog = new myLogger;

@nogc @property @safe LogLevel globalLogLevel();

@property @safe void globalLogLevel(LogLevel ll);
This methods get and set the global LogLevel.
Every log message with a LogLevel lower as the global LogLevel will be discarded before it reaches writeLogMessage method of any Logger.
class StdForwardLogger: std.experimental.logger.core.Logger;
The StdForwardLogger will always forward anything to the sharedLog.
The StdForwardLogger will not throw if data is logged with LogLevel.fatal.
Examples: 
auto nl1 = new StdForwardLogger(LogLevel.all);
@safe this(const LogLevel lv = LogLevel.all);
The default constructor for the StdForwardLogger.
Parameters:
LogLevel lv The LogLevel for the MultiLogger. By default the LogLevel is all.
@property @safe Logger stdThreadLocalLog();

@property @safe void stdThreadLocalLog(Logger logger);
This function returns a thread unique Logger, that by default propergates all data logged to it to the sharedLog.
These properties can be used to set and get this Logger. Every modification to this Logger will only be visible in the thread the modification has been done from.
This Logger is called by the free standing log functions. This allows to create thread local redirections and still use the free standing log functions.
Examples:
Ditto 
import std.experimental.logger.filelogger : FileLogger;
import std.file : deleteme, remove;
Logger l = stdThreadLocalLog;
stdThreadLocalLog = new FileLogger(deleteme ~ "-someFile.log");
scope(exit) remove(deleteme ~ "-someFile.log");

auto tempLog = stdThreadLocalLog;
stdThreadLocalLog = l;
destroy(tempLog);