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What Makes a Method Thread-safe? What are the rules?
Are there overall rules/guidelines for what makes a method thread-safe? I understand that there are probably a million one-off situations, but what about in general? Is it this simple?
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Assign same value to multiple variables at once?
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@Eoin: In doing $var_a = $var_b = ... = new Class();, all the variables will reference the same instance of Class.
– Tim Cooper
Jun 21 '19 at 19:34
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Why is 1/1/1970 the “epoch time”?
...ess than 829 days. For this reason, the time represented by the number 0 (called the epoch) had to be set in the very recent past. As this was in the early 1970s, the epoch was set to 1971-1-1.
Later, the system time was changed to increment every second, which increased the span of time that could...
What does “@” mean in Windows batch scripts
...off will turn this off for the complete batch file. However, the echo off call itself would still be visible. Which is why you see @echo off in the beginning of batch files. Turn off command echoing and don't echo the command turning it off.
Removing that line (or commenting it out) is often a help...
Why doesn't ruby support method overloading?
...; end; # second argument has a default value
method(10)
# Now the method call can match the first one as well as the second one,
# so here is the problem.
So ruby needs to maintain one method in the method look up chain with a unique name.
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How to zero pad a sequence of integers in bash so that all have the same width?
...uce the following output:
00010
00011
00012
00013
00014
00015
More generally, bash has printf as a built-in so you can pad output with zeroes as follows:
$ i=99
$ printf "%05d\n" $i
00099
You can use the -v flag to store the output in another variable:
$ i=99
$ printf -v j "%05d" $i
$ echo $j...
When would you use .git/info/exclude instead of .gitignore to exclude files?
...gnore rules, unlike .git/info/exclude.
So, .gitignore is available across all clones of the repository. Therefore, in large teams all people are ignoring the same kind of files Example *.db, *.log.
And you can have more specific ignore rules because of multiple .gitignore.
.git/info/exclude is av...
month name to month number and vice versa in python
...calendar module:
import calendar
{v: k for k,v in enumerate(calendar.month_abbr)}
Before Python (2.7+) you would do
dict((v,k) for k,v in enumerate(calendar.month_abbr))
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Any shortcut to initialize all array elements to zero?
...you can use java.util.Arrays.fill() (which will of course use a loop internally).
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Git: Merge a Remote branch locally
I've pulled all remote branches via git fetch --all . I can see the branch I'd like to merge via git branch -a as remotes/origin/branchname. Problem is it is not accessible. I can't merge or checkout.
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