No permisson to read output from NSTask ?

[Yen-Ju Chen]

I try to use NSTask to execute a perl scripts and read the result from
NSFileHandle.
But NSFileHandler raises an exception about having no permission to
read the output.
The scripts belongs to me and I have no problem running it.
NSFileHandle indeed can read the output *after* raise the exception.
I also try other scripps and have the same result.
Is there anything I did wrong ?
Do I need a special permission to read from standard output ?
How do I set it programmingly ?

Here is the code:

    NSFileHandle *f_output= [NSFileHandle fileHandleWithStandardOutput];
    NSTask *task = [[NSTask alloc] init];
    [task setStandardOutput: f_output];
    [task setLaunchPath: command];
    [task launch];
    NSData *data = [f_output readDataToEndOfFile];
    NSString *s = [[NSString alloc] initWithData: data encoding:
[NSString defaultCStringEncoding]];
    NSLog(@"%@", s);
    return;

Thanx.

Yen-Ju