Hi,

I'm developing a multiple threads application.
I need to log several events in the different threads into the same text 
file.
The add_2_log function is very simle:

using (StreamWriter sw = new StreamWriter(log_file_name,true))
{

sw.Write (DateTime.Now.Date.Day.ToString().PadLeft(2, '0') +"/" + 
DateTime.Now.Date.Month.ToString().PadLeft(2, '0') + "/" + 
DateTime.Now.Date.Year.ToString() + "," + DateTime.Now.TimeOfDay.ToString() 
+ "," + message + "," + code1.ToString() + "," + code2.ToString());

}



Do I need to add a Mutex in order to prevent thread trying to add a line 
while file is already open for current ?



Thanks,



MP

Yes a mutex would be required or a lock would work just as well.
-- 
Simon Hart
http://simonrhart.blogspot.com


"Moshe Peleg" wrote:


> Hi,
> 
> I'm developing a multiple threads application.
> I need to log several events in the different threads into the same text 
> file.
> The add_2_log function is very simle:
> 
> using (StreamWriter sw = new StreamWriter(log_file_name,true))
> {
> 
> sw.Write (DateTime.Now.Date.Day.ToString().PadLeft(2, '0') +"/" + 
> DateTime.Now.Date.Month.ToString().PadLeft(2, '0') + "/" + 
> DateTime.Now.Date.Year.ToString() + "," + DateTime.Now.TimeOfDay.ToString() 
> + "," + message + "," + code1.ToString() + "," + code2.ToString());
> 
> }
> 
> 
> 
> Do I need to add a Mutex in order to prevent thread trying to add a line 
> while file is already open for current ?
> 
> 
> 
> Thanks,
> 
> 
> 
> MP
> 
> 
> 

Using lock(obj) in C# would be preferred as this compiles to

Monitor.Enter(obj)
try
{
    //work
}
finally
{
    Monitor.Exit(obj);
}

Monitor exposes locking mechanics supported by the CLR.

Using a Mutex in managed code simply provides a managed wrapper around a 
kernal object and as such is the more heavyweight solution. Mutexes should 
really only be used where inter-process synchronisation is required.

"Simon Hart"  wrote in message 
news:59FD1322-3C45-420D-815C-94AFF8E6C31D@microsoft.com...

> Yes a mutex would be required or a lock would work just as well.
> -- 
> Simon Hart
> http://simonrhart.blogspot.com
>
>
> "Moshe Peleg" wrote:
>
>> Hi,
>>
>> I'm developing a multiple threads application.
>> I need to log several events in the different threads into the same text
>> file.
>> The add_2_log function is very simle:
>>
>> using (StreamWriter sw = new StreamWriter(log_file_name,true))
>> {
>>
>> sw.Write (DateTime.Now.Date.Day.ToString().PadLeft(2, '0') +"/" +
>> DateTime.Now.Date.Month.ToString().PadLeft(2, '0') + "/" +
>> DateTime.Now.Date.Year.ToString() + "," + 
>> DateTime.Now.TimeOfDay.ToString()
>> + "," + message + "," + code1.ToString() + "," + code2.ToString());
>>
>> }
>>
>>
>>
>> Do I need to add a Mutex in order to prevent thread trying to add a line
>> while file is already open for current ?
>>
>>
>>
>> Thanks,
>>
>>
>>
>> MP
>>
>>
>> 

Moshe Peleg wrote:


> Do I need to add a Mutex in order to prevent thread trying to add a
> line while file is already open for current ?


Yes - but keep in mind that if one thread blocks another because of logging, 
the flow of execution in your application has changed from what it would be 
without logging.

Ebbe

Thank you very much.

Does the same answer goes for timers ?
Is it the same for the "ordinary" control timers ?
I understand they are on the same thread, but the do interrupt the main 
program.
Therefore they also might cause the same problem.

"Ebbe Kristensen"  wrote in message 
news:%23eP5pgFyHHA.3400@TK2MSFTNGP03.phx.gbl...

> Moshe Peleg wrote:
>
>> Do I need to add a Mutex in order to prevent thread trying to add a
>> line while file is already open for current ?
>
> Yes - but keep in mind that if one thread blocks another because of 
> logging, the flow of execution in your application has changed from what 
> it would be without logging.
>
> Ebbe
> 

Yeah, how about having the threads submit log messages to a queue, and
have another thread reading from the queue and writing the log
messages to a file?

Matt

On Jul 17, 10:52 am, "Ebbe Kristensen"  wrote:

> Moshe Peleg wrote:
> > Do I need to add a Mutex in order to prevent thread trying to add a
> > line while file is already open for current ?
>
> Yes - but keep in mind that if one thread blocks another because of logging,
> the flow of execution in your application has changed from what it would be
> without logging.
>
> Ebbe