Non-blocking mode I/O either transfers at least one byte or returns immediately with an error or end of stream. Non-blocking algorithms refer to use of concurrency without the usual mutual exclusion primitives, guaranteeing that thread operations will not block indefinitely. This is usually handled with atomic value modification (increment/decrement) and/or reading (compare-and-exchange) operations.. It isn't clear which this tag is intended for.
Questions tagged [nonblocking]
1597 questions
21
votes
1 answer
What's the difference between async and nonblocking in unix socket?
I'm seeing such code in nginx:
if(fcntl(ngx_processes[s].channel[0], F_SETFL, fcntl(s, F_GETFL) | O_NONBLOCK) == -1) {
...
if (ioctl(ngx_processes[s].channel[0], FIOASYNC, &on) == -1) {
...
Anyone can tell me what's the difference between fcntl(s,…
cpuer
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21
votes
3 answers
Python - Timer with asyncio/coroutine
I am trying to set a timer that will interrupt the running process and call a coroutine when it fires. However, I'm not sure what the right way to accomplish this is. I've found AbstractEventLoop.call_later, along with threading.Timer but neither of…
Greg Miller
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21
votes
3 answers
How to readline infinitely in Node.js
while(1){
rl.question("Command: ",function(answer){
console.log(answer);
})
}
Just tried this code, but instead get input one by one, it blink the "Command: " line. I know node.js is non-blocking but i don't know how to fix this…
user2477
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21
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3 answers
Is it possible to do asynchronous / parallel database query in a Django application?
I have web pages that take 10 - 20 database queries in order to get all the required data.
Normally after a query is sent out, the Django thread/process is blocked waiting for the results to come back, then it'd resume execution until it reaches the…
Continuation
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21
votes
5 answers
How to use QThread correctly in pyqt with moveToThread()?
i read this article How To Really, Truly Use QThreads; The Full Explanation, it says instead of subclass qthread, and reimplement run(), one should use moveToThread to push a QObject onto QThread instance using moveToThread(QThread*)
here is the…
Shuman
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21
votes
2 answers
How to read named FIFO non-blockingly?
I create a FIFO, and periodically open it in read-only and non-blockingly mode from a.py:
os.mkfifo(cs_cmd_fifo_file, 0777)
io = os.open(fifo, os.O_RDONLY | os.O_NONBLOCK)
buffer = os.read(io, BUFFER_SIZE)
From b.py, open the fifo for writing:
out…
chaonin
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20
votes
5 answers
NodeJs how to create a non-blocking computation
I am trying to get my head around creating a non-blocking piece of heavy computation in nodejs. Take this example (stripped out of other stuff):
http.createServer(function(req, res) {
console.log(req.url);
sleep(10000);
res.end('Hello…
Tallmaris
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20
votes
6 answers
Detect key press (non-blocking) w/o getc/gets in Ruby
I have a simple task that needs to wait for something to change on the filesystem (it's essentially a compiler for prototypes). So I've a simple infinite loop with a 5 second sleep after the check for changed files.
loop do
# if files changed
#…
Robert K
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20
votes
5 answers
End of nonblocking file
How is end of file detected for a file in nonblocking mode?
Matt Joiner
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20
votes
2 answers
Tomcat NIO thread pools
I understand Java NIO (channels, selector, ..). I would like to understand Tomcat NIO better so that I can configure thread pools of Tomcat appropriately from Spring boot.
Can someone please explain what is the purpose of each thread pool and how do…
Rag
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20
votes
5 answers
Non-blocking sockets
What's the best way to implement a non-blocking socket in Java?
Or is there such a thing? I have a program that communicates with a server through socket but I don't want the socket call to block/cause delay if there is a problem with the…
jasonline
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20
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3 answers
Understanding NodeJS & Non-Blocking IO
So, I've recently been injected with the Node virus which is spreading in the Programming world very fast.
I am fascinated by it's "Non-Blocking IO" approach and have indeed tried out a couple of programs myself.
However, I fail to understand…
Vishwas Shashidhar
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3 answers
Explain Michael & Scott lock-free queue alorigthm
I am studying Michael & Scott's lock-free queue algorithm and trying to implemented it in C++.
But I produced a race in my code and think there may be a race in the algorithm.
I read the paper here:
Simple, Fast, and Practical Non-Blocking and…
Eddie Deng
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19
votes
4 answers
Is Tornado really non-blocking?
Tornado advertises itself as "a relatively simple, non-blocking web server framework" and was designed to solve the C10k problem. However, looking at their database wrapper, which wraps MySQLdb, I came across the following piece of code:
def…
ipartola
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18
votes
3 answers
socket select ()versus non-block recv
I've seen a few write-ups comparing select() with poll() or epoll(), and I've seen many guides discussing the actual usage of select() with multiple sockets.
However, what I can't seem to find is a comparison to a non-blocking recv() call without…
Gren Meera
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