On Mon, Mar 17, 2008 at 11:17:59AM -0400, Hal Vaughan wrote:
thread 2 could start, is that the same? Is there any way I can get the two threads to run concurrently? (I know true multi-tasking on a single CPU is
Yes, you need to properly synchronize between them. Thread A has to explicitly signal thread B to start running (while A puts itself to sleep). If you don't use such signalling, the OS has all right to assume that you don't care about the scheduling order.
just slicing up time, but by concurrently, I mean sharing resources instead of one taking up everything.)
"Sharing resources" is very vaguely defined. If thread A runs for 30 seconds, and then B for 30 seconds without interruption, they will still have received their fair share of resources if the total run time of the program is, say, 1 hour.
This is just a test program, but my big concern is that the program I'm writing does something like this. I'm controlling an HD radio through the serial port (or a usb port with a usb->RS232 adaptor). I know once I mention ports, I'm getting into OS specific stuff, but even beyond that issue, I'm trying to understand what I need to do and what's going on.
title, artist name, and so on. To read the port this way, I'm using an ifstream object to open the port as a file, which seems to work well because it's buffered. Then, in another thread, I write the commands to
Using buffered I/O with external devices is a bad idea, IMHO.
This all goes in a library where the listening thread can be started and stopped. I don't want to miss incoming data on the ifstream object, but it seems if I let that thread run on it's own, the other thread to pass on
The thread won't be running on its own if there's no data - it'll go to sleep and other threads will be scheduled.
I know in Perl I can fork and have one thread continue to do it's own thing without it seeming to effect the other. I also know Perl is a much higher
I don't think that Perl's threads are "real" OS-threads.
So is there no way to create a thread and not have it take up all the CPU time until it's done without using SMP? (This is going to be for
Well, yes, threads sleep on I/O when I/O is not possible at the given moment.