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Old 02-13-2018, 07:51 AM   #1
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Question Unblocking a Process on Two or More Triggers

I am programming a Linux application for an embedded system - the processor is an ARM-Cortex-7 but I'm finding that I can build the code on all sorts of targets with little or no changes.

Anyway, I've run into a delemma: I have processes that block waiting for input from sockets or input from queues or input from USB-serial ports - things like that. It's all very straight-forward.

What I am finding difficult is arranging for a process to unblock itself on an "Either-OR" basis. For example, maybe I have a process that waits for input from a queue but I might also want it to wake up periodically on a timer.

How is this done, generally? Is there are "general" way of doing this or am I being a bit naive? I am finding it surprising how difficult this is.

Thank you,
Old 02-13-2018, 10:57 PM   #2
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How about select or poll
Or SIGIO? Or aio?
Old 02-14-2018, 07:05 AM   #3
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Hi Jethro63, I wrote a blog entry about Select.

There are also other Linux programming applications blog entries about a USB receiver/parser, a controlling/monitoring daemon process, and other entries if you wish to peruse.

I feel select() is a great option. You could also consider threads, but generally I prefer processes.
Old 02-14-2018, 12:36 PM   #4
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Thanks guys.
I had not known about select() and I had spent a lot of time looking around. It seems like you just have to enter the right search parameters.
I will give this a try.


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