Multiple applications write to one console - mixed/messed output - windows

Question

I have the following system architecture (cannot be changed - legacy code): One main application invokes one or more other applications and these applications interact over a IP protocol.
All applications write to one console window. Unfortunately the console output can get messed up (one character from app 1, next char from app 2, next character from app 4 etc.).
All applications write to console via one Logger.dll (provides static logging functions) using cout/cerr.
Is there a way how I can prevent mixed logging messages in this setup?
Thanks in advance.
EDIT code added:
void Logger::Log(const std::string & componentName, const std::string & Text, LogLevel logLevel, bool logToConsole, bool beep)
{
std::ostringstream stream;
switch (logLevel)
{
case LOG_INFO:
if (logToConsole)
{
stream << componentName << ": INFO " << Text;
mx_console.lock(); // this is a static boost::mutex
std::cout << stream.str() << std::endl;
std::cout.flush();
mx_console.unlock();
}
break;
case LOG_STATUS:
stream << componentName << ": STATUS " << Text;
mx_console.lock();
std::cout << stream.str() << std::endl;
std::cout.flush();
mx_console.unlock();
break;
case LOG_WARNING:
stream << componentName << ": WARNING " << Text;
mx_console.lock();
std::cout << stream.str() << std::endl;
std::cout.flush();
mx_console.unlock();
break;
default:;
}
if (beep)
Beep( 500, 50 );
}

Answer 1

Since you have separate logging functionality you can at minimum use some kind of locking (global mutex, etc.) to avoid interspersing messages from different applications too much. To make it more readable and grepable, add some identifying information, like process name or PID. Wrapping your Logger.dll around existing logging library sounds like an option as well.
Alternatively, you could have logging functions just forward messages to your main application and let that to sort out the synchronization and interspersing.

Answer 2

Syslog might be a solution for you as it is intended to handle logs from various places. Syslog is developed for unix, but this answer shows versions for windows.
You can change your logger to log to syslog instead of the console.

Answer 3

I replaced now all the
std::cout << stream.str();
statements with
std::string str = stream.str();
printf(str.c_str());
and now the output isn't messed up character-wise anymore.
But I don't have a good explanation for this behavior, does anybody know why?