Call ofLog() from a thread

Hi,
I was reading at ofThread example, and I wonder what happens if I call ofLog() from different threads ?
Log file could be a mess because lines are going to be merged ?

Update:
I just made a quick test, here is my result in the console (look at last line):

[warning] threadedFunction(): 123456789
[warning] main thread(): abcdefghi
[warning] main thread(): abcdefghi
[warning] threadedFunction(): 123456789
[warning] main thread(): abcdefghi
[[warningwarning] ] threadedFunction()main thread(): : 123456789abcdefghi

The code is :

void threadedFunction()
{
   while(isThreadRunning())
    {
        ofLogWarning("threadedFunction()") << "123456789";
        sleep(10)
     }
} 

and

void ofApp::draw()
{
    ofLogWarning("main thread()") << "abcdefghi";
}

How can I prevent this ?