Logs, Printing Class Name, Function Name, Line Number

From UE4: Community Wiki
Jump to: navigation, search


This is a legacy article imported from the old wiki.
An updated version can be found here: Logging


Overview

You can even get a UE4 FString telling you the whole function signature of the function you are in, including variable types!

Print Screen Messages With Class/LineNumber

You also get a pre-processor command that prints a message to the screen including the class name and line number!

JoyStringCurrentClassFuncLineNumber2.jpg

//~~~ Tick ~~~
void AEVCoreDefense::Tick(float DeltaTime)
{
	Super::Tick(DeltaTime);
	//~~~~~~~~~~~~~

	VSCREENMSG("Got Here!");  //Class and line number get printed for you! ÔÖÑ Rama
}

Print the name of the Calling Function, With Entire Signature!

JoyStringCurrentClassFuncLineNumber3.jpg

Code

Simply put this somewhere at the top of one of your core classes.

// Joy Class Func Line
#include "JoyCurrentClassFuncLine.h"
/*
	Joy String 
		Current Class, File, and Line Number!
			by Rama
			
	PreProcessor commands to get 
		a. Class name
		b. Function Name
		c. Line number 
		d. Function Signature (including parameters)
		
	Gives you a UE4 FString anywhere in your code that these macros are used!
	
	Ex: 
		You can use JOYSTR_CUR_CLASS anywhere to get a UE4 FString back telling you 
		what the current class is where you called this macro!
	
	Ex:
		This macro prints the class and line along with the message of your choosing!
		VSCREENMSG("Have fun today!");
	<3  Rama
*/
#pragma once

//Current Class Name + Function Name where this is called
#define JOYSTR_CUR_CLASS_FUNC (FString(__FUNCTION__))

//Current Class where this is called
#define JOYSTR_CUR_CLASS (FString(__FUNCTION__).Left(FString(__FUNCTION__).Find(TEXT(":"))) )

//Current Function Name where this is called
#define JOYSTR_CUR_FUNC (FString(__FUNCTION__).Right(FString(__FUNCTION__).Len() - FString(__FUNCTION__).Find(TEXT("::")) - 2 ))
  
//Current Line Number in the code where this is called
#define JOYSTR_CUR_LINE  (FString::FromInt(__LINE__))

//Current Class and Line Number where this is called
#define JOYSTR_CUR_CLASS_LINE (JOYSTR_CUR_CLASS + "(" + JOYSTR_CUR_LINE + ")")
  
//Current Function Signature where this is called
#define JOYSTR_CUR_FUNCSIG (FString(__FUNCSIG__))

//Victory Screen Message
// 	Gives you the Class name and exact line number where you print a message to yourself
#define VSCREENMSG(Param1) (GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, *(JOYSTR_CUR_CLASS_LINE + ": " + Param1)) )

#define VSCREENMSG2(Param1,Param2) (GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, *(JOYSTR_CUR_CLASS_LINE + ": " + Param1 + " " + Param2)) )

#define VSCREENMSGF(Param1,Param2) (GEngine->AddOnScreenDebugMessage(-1, 5.f, FColor::Red, *(JOYSTR_CUR_CLASS_LINE + ": " + Param1 + " " + FString::SanitizeFloat(Param2))) )

//UE LOG
#define V_LOG(LogCat, Param1) 		UE_LOG(LogCat,Warning,TEXT("%s: %s"), *JOYSTR_CUR_CLASS_LINE, *FString(Param1))

#define V_LOG2(LogCat, Param1,Param2) 	UE_LOG(LogCat,Warning,TEXT("%s: %s %s"), *JOYSTR_CUR_CLASS_LINE, *FString(Param1),*FString(Param2))

#define V_LOGF(LogCat, Param1,Param2) 	UE_LOG(LogCat,Warning,TEXT("%s: %s %f"), *JOYSTR_CUR_CLASS_LINE, *FString(Param1),Param2)

#define V_LOGM(LogCat, FormatString , ...) UE_LOG(LogCat,Warning,TEXT("%s: %s"), 	*JOYSTR_CUR_CLASS_LINE, *FString::Printf(TEXT(FormatString), ##__VA_ARGS__ ) )

V_LOG

Each of the V_LOG Macros takes as the first parameter the log category that you want to use

#define V_LOG(LogCat, Param1)   UE_LOG(LogCat,Warning,TEXT("%s: %s"), *JOYSTR_CUR_CLASS_LINE, *FString(Param1))

V_LOGM

V_LOGM is special in that you can have an arbitrary number of vars that you output, and of any type, similar to standard UE_LOG functionality

Example usage:

int32 Health = 100;
float ArmorPct = 52.33;
FVector Location(33,12,1);
	
V_LOGM(Joy, "Health: %d, ArmorPct: %f, Loc: %s",  Health, ArmorPct, *Location.ToString());

More Info

VS C++ Predifined Macros

Variadic Macros