Several error_log() messages on same line in error log - apache

Question

I have this PHP code :
error_log('my message 1');
....
error_log('my message 2');
...
error_log('my message 3');
This produces in apache error_log one line with all messages :
[Wed Nov 13 17:24:55.880399 2013] [proxy_fcgi:error] [pid xx] [client xxx] AH01071: Got error 'PHP message: my message 1\n'PHP message: my message 2\n'PHP message: my message 3
My config :
Apache 2.4
PHP : 5.4
PHP-FPM with proxypassmatch directive.
My question : Why messages are on the same line, and how to do to have one line per message ?
Thanks for yours answers.
EDIT
One line per message should look like :
[Wed Nov 13 17:24:55.880399 2013] [proxy_fcgi:error] [pid xx] [client xxx] AH01071: Got error 'PHP message: my message 1'
[Wed Nov 13 17:24:55.880399 2013] [proxy_fcgi:error] [pid xx] [client xxx] AH01071: Got error 'PHP message: my message 2'
[Wed Nov 13 17:24:55.880399 2013] [proxy_fcgi:error] [pid xx] [client xxx] AH01071: Got error 'PHP message: my message 3'

Answer 1

error_log("error message \r\n");
PHP disregards special ASCII characters within single quotes(it renders it as separate chars), you need to use double quotes.
In addition:
You should open your php.ini file, the one in the /etc/php5/apache2/ folder, and chnage the error_log directive to point to a file.
It is important that Apache will have sufficient privileges to write into this file.
so
chown www-data:www-data /var/www/somefile.log
should do it
If it's currently undefined, the logs will go through syslog, and there new lines are not allowed.
Additional edit:
To penetrate output buffering you need to raise an exception.
example:
try{
ob_start();
doSomething($userInput);
ob_end_flush();
}
catch(Exception $e){
error_log($e->getMessage());
}
function doSomething($data = null){
if($data === null){
throw new Exception("Data is required");
}
else{
//do something
}
}

Answer 2

User \r\n
error_log("my message 1\r\n");
....
error_log("my message 2\r\n");
...
error_log("my message 3\r\n");