> -----Original Message----- > From: Erick Thompson [mailto:[EMAIL PROTECTED]] > > I have an application that uses an external process/utility > (pdftotext.exe) > that is normally called from a command window. I use > ProcessStartInfo and > Process to manage the external utility.
> There are multiple threads running this application. This statement doesn't make sense for the reasons you suspect below. Either your application has many threads that start instances of pdftotext.exe or you happen to know that pdftotext.exe is multithreaded. I imagine the first case is the one you are interested in since the threads in pdftotext.exe do not interact directly with your application's threads. You will have to go out of your way to communicate between threads in your app and pdftotext.exe because the memory address spaces of each process are protected from each other. > My concern is that if two thread try to use the > application at the same time, there will be problems, as I > don't know if the > utility is thread safe. The question to ask is: "Can multiple instances of pdftotext.exe run safely". If I had to guess I would say they can but you have to make sure of this. Again, the threads from different instances of pdftotext.exe do not interact like threads in a single process/AppDomain can. > By using a process object, am I avoiding threading > problems because a new process is created, so the threads > will never cross? Yep. Though the notion that you are "avoiding threading problems" is a little misleading. IMO, If you have multiple threads you will at one time or another have threading problems. That's just the nature of MT programming - its tricky. :) > If not, what is best way to make sure that only one thread at a time is > using the external utility. You would have to virtualize the pdftotext.exe resource so you could serialize your AppDomain's threads. Create a PDFToTextTool class with a Doit() method that invokes pdftotext.exe. You can use all the FCL thread synchronization tools to serialize threads into that method. But again you may not care if multiple instances of pdftotext.exe can run simultaneously. Then the question becomes a scalability one - is it really expensive to run multiple instances of pdftotext.exe? Does my app perform better if a share an instance etc. Jim You can read messages from the DOTNET archive, unsubscribe from DOTNET, or subscribe to other DevelopMentor lists at http://discuss.develop.com.
