[Brass]

I'm finding Cocoa's NSFileHandle a little difficult to come to grips with. I guess I'm just thinking the wrong way, or something.

Anyhow, can anyone give me some idea of how to either redirect stdout (of my App's process) and place the text in an NSTextView, or otherwise, how to read from the existing stdout and place the text in an NSTextView.

I'm sure this has got to be very simple, but I just can't figure it out.

[Samad]

Here are some thoughts off the top of my head:
1) Close stdout (id = 1) and open it up to another file with an id = 1. Read that file to get stdout. I'm not too sure how to do this but it might be possible.
2) Have another process read from your program's output by a pipe, then send that back to your program. This is guaranteed to work, but requires some work.

If you want to read the stdout of another process, you'll have to use NSPipe (which is just a wrapper class for the Posix pipe() call).

[Samad]

Here's an example on reading the output of a program:

//Create a task
NSTask *task = [[NSTask alloc] init];

// Create a pipe for communicating with task
NSPipe *pipe = [[NSPipe alloc] init];

// Create a file handle to read from the pipe, because pipes are just file handles
NSFileHandle *fh = [pipe fileHandleForReading];

// Assign a launch path to the task
[task setLaunchPath: @"/bin/ls"];

// Assign the arguments to the task
[task setArguments: [NSArray arrayWithObject @"/"]];

// Assign the stdout of the task to the pipe
[task setStandardOutput: pipe];

// Launch the task; this method does not return until the process has ended
[task launch];

// Get the data from the file handle
NSData *stdoutData = [fh availableData];

// Display stdoutData
NSLog(@"%s", [stdoutData bytes]);

[Brass]

That makes sense, but what about stdout for something other than an NSTask? I want to capture stdout for my entire application (ie, I want to be able to capture NSLog output as well).

[Brass]

Just for reference I've got this all working now, and solved some problems along the way:

calling [fh availableData] is best done after receiving a notification that there is available data to be read (otherwise the thread blocks)

need to register for this notification before receiving data, and in the callback, if you want to receive more data