danielblagy / yelloger

Simple thread-safe single-header C++ 17 logger.

Yelloger

• General Info
• Reference

A simple thread-safe single-header C++ 17 logger.

Motivation

This logger was initially made for a Youtube tutorial.

Include

This is a header-only library consisting of one header file. Simply copy the include/yelloger.h file and #include it in your project.

Simple Example

Console logging (the simplest use case)

#include <yelloger.h>

int main()
{
	const char* name = "User";
	Yellog::Info("Hello %s", name);
	
	return 0;
}

Output:

15:07:31 15-02-2021 [Info] Hello User

Quick Start

Yellog doesn't need to be instantiated, just include the header and use it like this

	Yellog::Info("Infotmation %d", int_value);

, also there is no need to put newline character at the end of the message, it will be done automatically.

Reference Contents

• Log Priorities
• Logging
• File Output
• Timestamps

Reference

Log Priorities

The default log priority is Yellog::InfoPriority. You can set priority by calling

	Yellog::SetPriority(Yellog::DebugPriority);	// e.g. Yellog::DebugPriority

Possible values:

	Yellog::TracePriority
	Yellog::DebugPriority
	Yellog::InfoPriority
	Yellog::WarnPriority
	Yellog::ErrorPriority
	Yellog::CriticalPriority

You can get priority by calling

	Yellog::GetPriority();	// will return Yellog::InfoPriority if Yellog::SetPriority hasn't been called before

Logging

To log:

	Yellog::Trace(const char* message, Args... args)		// log a message with trace priority
	Yellog::Debug(const char* message, Args... args)		// log a message with debug priority
	Yellog::Info(const char* message, Args... args)			// log a message with info priority
	Yellog::Warn(const char* message, Args... args)			// log a message with warn priority
	Yellog::Error(const char* message, Args... args)		// log a message with error priority
	Yellog::Critical(const char* message, Args... args)		// log a message with critical priority

As args you can provide primitives and C-strings. Formatting follows printf format.

File Output

To enable file output, call

	Yellog::EnableFileOutput("mylogpath/mylog.txt");

before using the logger.

Optionally, you can provide no path

	Yellog::EnableFileOutput();

then, the logs will be saved in '/log.txt'.

To get the current filepath for file logging, call

	Yellog::GetFilepath();

if file output was not enabled, the filepath will contain NULL, otherwise a const char* value will be returned.

To check if file output was enabled and file was successfully opened, call

	Yellog::IsFileOutputEnabled();	// returns true if success, false if failure

Timestamps

Format follows ctime strftime format specification.
Default format is "%T %d-%m-%Y" (e.g. 13:20:25 14-02-2021).
4 spaces are added automatically to the end of timestamp each time the message is logged.

To set a log timestamp format, call

	Yellog::SetTimestampFormat("%c");	// e.g. Thu Aug 23 14:55:02 2001

To get the current log timestamp format, call

	Yellog::GetTimestampFormat();	// e.g. "13:20:25  14-02-2021"