Sharing the same log file from concurrent two processes

[Giovanni Parodi]

Hello everybody,
I have a question about logging with log4cxx from different process.
I have two different .exe that link the same log4cxx dll.
I would like that both the exe uses the same configuration file and so
write in the same log file.
I was able to get this result, however I think that I did something wrong.

I'm generating two .exe by building the attached cpp code, and both load
the conf file in attachment.

When I run the exes, it seems that everything works fine, and the log file
example.log is fine.
However I don't understand if my approach is fine.
That is, how it is possible that the two processes don't access at the same
time the log file generating by this way a conflict and corrupting it?

I think that I should generate a logging exe that receives the messages
from other processes and that then, from a single exe, I should access the
log.
Is there any suggestion? I'm a bit confused, any link/idea/feedback will be
appreciated

#include <stdlib.h>
using namespace com::foo;

// include log4cxx header files.
#include "log4cxx/logger.h"
#include "log4cxx/basicconfigurator.h"
#include "log4cxx/propertyconfigurator.h"
#include "log4cxx/helpers/exception.h"

using namespace log4cxx;
using namespace log4cxx::helpers;
// Define a static logger variable so that it references the
// Logger instance named "MyApp".
LoggerPtr logger(Logger::getLogger("MyApp"));

int _tmain(int argc, _TCHAR* argv[])
{
	SYSTEMTIME localTime;
	GetLocalTime(&localTime);

	std::srand(localTime.wSecond); //use current time as seed for random generator
	// Variabile differente per ogni istanza del processo
	int processId = std::rand();

	int result = EXIT_SUCCESS;
	try
	{
		if (1)
		{
			// Vedo solo gli errori di foo
			PropertyConfigurator::configure("\\Flashdisk\\log4j2.conf");
			// Vedo tutto di foo
			//PropertyConfigurator::configure("\\Flashdisk\\log4j.conf");
		}
		else
		{
			BasicConfigurator::configure();
		}

		std::string	testo;
		
		int counter = 0;
		while(1)
		{
			counter++;

			LOG4CXX_INFO(logger, ">>>>> " << processId << " Entering Contatore " << counter);
	
			LOG4CXX_INFO(logger, "<<<<< " << processId <<" Leaving Contatore " << counter);
			
			// Aspetto un po`, time variabile tra un processo e l'altro
			Sleep(localTime.wSecond*50);
		}
	}
	catch(Exception&)
	{
			result = EXIT_FAILURE;
	}

	return result;
}

log4j2.conf
Description: Binary data