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Difference between malloc and calloc?
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calloc() gives you a zero-initialized buffer, while malloc() leaves the memory uninitialized.
For large allocations, most calloc implementations under mainstream OSes will get known-zeroed pages from the OS (e.g. via POSIX mm...
What is the difference between exit() and abort()?
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abort() exits your program without calling functions registered using atexit() first, and without calling objects' destructors first. exit() does both before exiting your program. It does not call destructors for automatic objects though. So
A a;
void test() ...
What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...bar', so loop runs once and
done # prints nothing (actually "")
var="foo bar"
for i in "${var}bar"; do # Expands to 'for i in "foo barbar"; do...'
echo $i # so runs the loop once
done
# foo barbar
Note that "${var}bar" in the second example above could also ...
difference and when to use getApplication(), getApplicationContext(), getBaseContext() and someClass
...text( ), getBaseContext() , getContext() and someClass.this and especially when to use the these methods in the following code lines:
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C# int to byte[]
...sides, doing the assignment is cheap since it does not copy the memory nor allocate new memory, it just adds a new name to the already allocated array. So why not do it?
– paracycle
May 7 '19 at 15:54
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What is the difference between pluck and collect in Rails?
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When you do:
User.first.gifts.collect(&:id)
You have objects with all fields loaded and you simply get the id thanks to the method based on Enumerable.
So:
if you only need the id with Rails 4, use ids: User.first.gifts.ids
if you only need some fields with Rails 4, use pluck: User.first...
How to start two threads at “exactly” the same time
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// Now if we block on the gate from the main thread, it will open
// and all threads will start to do stuff!
gate.await();
System.out.println("all threads started");
This doesn't have to be a CyclicBarrier, you could also use a CountDownLatch or even a lock.
This still can't make sure that ...
In Vim, how do I apply a macro to a set of lines?
...at performs an operation on a single line. I want to repeat that macro on all of the remaining lines in the file. Is there a quick way to do this?
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Browse orphaned commits in Git
...is open I think I'll give an answer to my own question. Using git reflog --all is a good way to browse orphaned commits - and using the SHA1 hashes from that you can reconstruct history.
In my case though, the repository was corrupted so this didn't help; git fsck can help you find and sometimes fi...
Flexbox not giving equal width to elements
...t has up to 5 items and as little as 3, but it's not dividing the width equally between all the elements.
2 Answers
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