how to write log file in C++

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5.00/5 (1 vote)

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Hello all Programmer,

Can anybody help me to write log file in c++ or provide me the pointer or some code snippet for same.

thanks
Sampath

Posted 28-Jul-10 3:36am

SampathKumarAmarthaluri

Updated 30-Aug-22 22:51pm

ThatsAlok

v3

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Comments

Kristian Sixhøj 28-Jul-10 9:48am

I'm sure someone here can, but you have to be a bit more specific. What exactly are you having trouble with?

ThatsAlok 17-Aug-10 2:20am

If it MFC, you can use CStdioFile, i know it's c++ based question. thats why posting as comment!

The Manoj Kumar 17-Aug-10 2:29am

One question for you, what is the difference between writing a file and writing a log file? Aren't they same except the information to write to it.

7 solutions

Solution 5

you can use the log file library present in codeproject
A Simple LogFile[^]

Posted 6-Mar-12 20:33pm

Chandrakantt

Solution 6

log file is basically a text file. So you can use file writing functions to write logs on to it. Logs normally contains TimeStamp + Error Code + and a small single line description mentioning the problem

Posted 6-Mar-12 22:01pm

jk chan

Solution 4

Simply open a text file and redirect the standard output to the file..

Simple Logger in C[^]

Edit: Updated the link to point to the logger.

Posted 15-Aug-10 22:04pm

varun85gupta

Updated 11-Feb-13 0:46am

v4

Comments

Niklas L 16-Aug-10 4:41am

Reason for my vote of 2
One would expect a link to someones own site actually pointing to the solution of the problem.

Solution 9

Hi Try it:
#include <iostream>
#include <cstdio>

int main(int argc, char* argv[])
{
using namespace std;
freopen( "output.txt", "w", stdout );
freopen( "error.txt", "w", stderr );

cout << "Output message" << endl;
cerr << "Error message" << endl;
}
Yours Farhad.

Posted 10-Dec-13 22:30pm

farhad Najib

Comments

CHill60 11-Dec-13 9:30am

Reasons for my downvote. The question is over 3 years old and already adequately answered; this will not even compile (#include #include)

Solution 11

#define LOG_FILE "Temp.png"
void saveData(std::string data)
{
std::fstream logFile;
// Open File
logFile.open(LOG_FILE, std::ios::app);
//Write data into log file
logFile << data;
// close file stream
logFile.close();

}

Posted 30-Aug-22 22:51pm

Member 15753255

Updated 30-Aug-22 22:52pm

v2

Comments

CHill60 31-Aug-22 5:37am

You have added nothing new to this 12 year old thread

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Aescleal · Accepted Answer · 2010-07-28T04:52:00

I'll see the C answer given earlier and raise a C++ answer for the same thing:

#include <fstream>

void write_text_to_log_file( const std::string &text )
{
    std::ofstream log_file(
        "log_file.txt", std::ios_base::out | std::ios_base::app );
    log_file << text << std::end;
}

It'll do the same thing with the bonus that if the file fails to open for whatever reason it won't crash in a steaming heap of undefined behaviour.

Cheers,

Ash

PS the important bits of logging for when you write your own are:

- flush after every message - std::endl does that

- close the file after every message - the fstream destructor does that

E.F. Nijboer · Accepted Answer · 2010-07-28T04:03:00

Solution 1

Hi Sampath,

C#

#include "stdio.h"
void WriteLogFile(const char* szString)
{
  #IFDEF DEBUG

  FILE* pFile = fopen("logFile.txt", "a");
  fprintf(pFile, "%s\n",szString);
  fclose(pFile);

  #ENDIF

}

This is the most simple way to append simple log strings to a file if DEBUG is defined.

Good luck!

Posted 28-Jul-10 4:03am

E.F. Nijboer

Comments

Albert Holguin 11-Feb-13 10:59am

Easy as that.... +5

how to write log file in C++

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