Hello all, I am having some trouble with capturing and redirecting stdout in my Cocoa application. A little bit of background: My app has an embedded scripting language interpreter, and I would like to redirect stdout in order to display the results of executed scripts in an NSTextView.
I've followed the approach described in the solution to StackOverflow question: http://stackoverflow.com/questions/2406204 To summarize, I use dup2() to "bind" stdout to my own NSPipe, and then add an NSNotification observer to listen for an NSFileHandleReadCompletionNotification on the NSPipe; the notification callback then reads the NSPipe. NSFileHandle readInBackgroundAndNotify is used to asynchronously read the data. This approach works, for the most part -- when executed scripts print only a small amount of data to stdout, my app redirects the output to an NSTextView successfully. However, when executed scripts print a large amount of data to stdout, the app hangs. I think the problem is that the pipe buffer is not being flushed/read when it's full; when the pipe is full, the script interpreter then is blocked because it's waiting for the pipe to empty so that it can write. I've also tried using an pseudo-tty via openpty() instead of an NSPipe, but I get the same problem: The app hangs when too much output is sent to stdout by an executing script. I'm sure that what I want to do is possible -- after all, the Xcode debugger console has no problems displaying stdout when running the same script that hangs my app. I guess my question is: How do I deal with a large amount of data that's printed to stdout in this situation? Is there some configuration I can use to change the buffering behavior (I've read elsewhere that stdout is block-buffered by default)? Is there a way to force NSFileHandle readInBackgroundAndNotify to read the pipe more frequently? Or is there something else? Thanks very much in advance, Edmond _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
