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What is the size of an enum in C?
...set of enum values, but I need each enum value to be 64 bits wide. If I recall correctly, an enum is generally the same size as an int; but I thought I read somewhere that (at least in GCC) the compiler can make the enum any width they need to be to hold their values. So, is it possible to have an e...
How to delete images from a private docker registry?
I run a private docker registry, and I want to delete all images but the latest from a repository. I don't want to delete the entire repository, just some of the images inside it. The API docs don't mention a way to do this, but surely it's possible?
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Forward declaring an enum in C++
...can't know the storage required for the enum variable. C++ Compiler's are allowed to specify the actual storage space based on the size necessary to contain all the values specified. If all that is visible is the forward declaration, the translation unit can't know what storage size will have been...
How to validate an email address using a regular expression?
...he IP address pattern that is floating around the internet with a bug that allows 00 for any of the unsigned byte decimal values in a dot-delimited address, which is illegal. The rest of it appears to be consistent with the RFC 5322 grammar and passes several tests using grep -Po, including cases d...
How to base64 encode image in linux bash / shell
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You need to use cat to get the contents of the file named 'DSC_0251.JPG', rather than the filename itself.
test="$(cat DSC_0251.JPG | base64)"
However, base64 can read from the file itself:
test=$( base64 DSC_0251.JPG )
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What does cherry-picking a commit with Git mean?
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This is in contrast with other ways such as merge and rebase which normally apply many commits onto another branch.
Make sure you are on the branch you want to apply the commit to.
git checkout master
Execute the following:
git cherry-pick <commit-hash>
N.B.:
If you cherry-pick f...
What is the performance cost of having a virtual method in a C++ class?
...3ghz in-order PowerPC processor. On that architecture, a virtual function call costs 7 nanoseconds longer than a direct (non-virtual) function call.
So, not really worth worrying about the cost unless the function is something like a trivial Get()/Set() accessor, in which anything other than inli...
How do you execute an arbitrary native command from a string?
...her path\file.ext"'
iex "& $command"
Likely, you could handle nearly all cases by detecting if the first character of the command string is ", like in this naive implementation:
function myeval($command) {
if ($command[0] -eq '"') { iex "& $command" }
else { iex $command }
}
But...
How do I sort a vector of pairs based on the second element of the pair?
...response to your edits to your question, here's some thoughts ...
if you really wanna be creative and be able to reuse this concept a lot, just make a template:
template <class T1, class T2, class Pred = std::less<T2> >
struct sort_pair_second {
bool operator()(const std::pair<T1...
Best algorithm for detecting cycles in a directed graph [closed]
What is the most efficient algorithm for detecting all cycles within a directed graph?
14 Answers
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