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Is there a way for multiple processes to share a listening socket?
...POSIX type OS), using fork() will cause the forked child to have copies of all the parent's file descriptors. Any that it does not close will continue to be shared, and (for example with a TCP listening socket) can be used to accept() new sockets for clients. This is how many servers, including Apac...
Python argparse mutual exclusive group
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add_mutually_exclusive_group doesn't make an entire group mutually exclusive. It makes options within the group mutually exclusive.
What you're looking for is subcommands. Instead of prog [ -a xxxx | [-b yyy -c zzz]], you'd have:
p...
Very Long If Statement in Python [duplicate]
...ther_long_identifier and
here_is_another_long_identifier != and_finally_another_long_name):
# ... your code here ...
pass
share
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follo...
What is the purpose of the “role” attribute in HTML?
...efine the default accessibility role of a web component. Even if/once that API is standardized, there may be need to override the default role of a component.
Note/Reply
You also wrote:
I see some people make up their own. Is that allowed or a correct use of the role attribute?
That's an allowed u...
Why are preprocessor macros evil and what are the alternatives?
I have always asked this but I have never received a really good answer; I think that almost any programmer before even writing the first "Hello World" had encountered a phrase like "macro should never be used", "macro are evil" and so on, my question is: why? With the new C++11 is there a real alte...
When to use in vs ref vs out
...ss you need ref.
It makes a big difference when the data needs to be marshalled e.g. to another process, which can be costly. So you want to avoid marshalling the initial value when the method doesn't make use of it.
Beyond that, it also shows the reader of the declaration or the call whether the ...
Extracting bits with a single multiplication
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A multiplication is a bunch of shift-and-add operations. The key is to allow overflow to "shift away" the bits we don't need and put the ones we want in the right place.
Multiplication by 4 (00000100) would shift everything left by 2 and get you to a00b0000 . To get the b to move up we need to...
mongodb, replicates and error: { “$err” : “not master and slaveOk=false”, “code” : 13435 }
...
You have to set "slave okay" mode to let the mongo shell know that you're allowing reads from a secondary. This is to protect you and your applications from performing eventually consistent reads by accident. You can do this in the shell with:
rs.slaveOk()
After that you can query normally from ...
How to access custom attributes from event object in React?
...: function(i) {
// do whatever
},
Notice the bind(). Because this is all javascript, you can do handy things like that. We no longer need to attach data to DOM nodes in order to keep track of them.
IMO this is much cleaner than relying on DOM events.
Update April 2017: These days I would wri...
How do you get the logical xor of two variables in Python?
...e not comparing apples to oranges, is "if xor( isApple(x), isApple(y) )" really clearer than "if isApple(x) != isApple(y)" ? Not to me!
– AmigoNico
May 21 '12 at 18:27
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