cocoa help please

[mfhaque]

i'm making a program that uses the unix command uptime..

- (IBAction)getuptimeid)sender
{
uptime = [[NSTask alloc] init];
[uptime setLaunchPath"/usr/bin/uptime"];
foo = [uptime launch];
[textField setObjectValue:foo];
[uptime release];
}

how can i grab the results from uptime and display it in a textField. i declares foo as a NSString but that doesn't work. any ideas please.

 

[rharder]

You need to use NSPipe.

It works something like this (taken from http://developer.apple.com/techpubs...e/Foundation/ObjC_classic/Classes/NSPipe.html):

NSPipe *taskPipe = [NSPipe pipe];
NSFileHandle *readHandle = [taskPipe fileHandleForReading];
NSData *inData = nil;
NSString *myString, *tempString;

uptime = [[NSTask alloc] init]; 
[uptime setLaunchPath:@"/usr/bin/uptime"]; 
[uptime setStandardOutput:taskPipe];
[uptime launch]; 

while ((inData = [readHandle availableData]) && [inData length]) {
        tempString= [[NSString alloc] initWithData:inData encoding:NSASCIIStringEncoding];
        myString = [myString stringByAppendingString:tempString];
        [tempString release];  // Not sure if you need this.
}

[textField setStringValue myString];

Can anyone see if I missed something glaring?

With 'uptime' it's not so bad, but with long-running apps you have to use some other tricks to gather all the output without locking up the event thread (which is what's calling those IBAction-type functions).

-Rob

 

[mfhaque]

wow, i was starting to feel like i wasn't gonna get a reply, thanks. i'm going to try your method.

 

[MikeySquid]

hey, that's pretty darn cool. Thanks, rharder.

 

[endian]

[tempString release];  // Not sure if you need this.

Yes you do need it, because you alloc/inited the string above. If you use one of the 'convenience constructors' like

 [NSString stringWithDate]

that usually begin with string, array or whatever it's returning, the returned object is autoreleased, so releasing it manually isnt necessary. See http://www.stepwise.com/Articles/Technical/2001-03-11.01.html