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What does the ??!??! operator do in C?
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??! is a trigraph that translates to |. So it says:
!ErrorHasOccured() || HandleError();
which, due to short circuiting, is equivalent to:
if (ErrorHasOccured())
HandleError();
Guru of the Week (deals with C++ but relevant here), where I picked this up.
Pos...
Bash tool to get nth line from a file
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head and pipe with tail will be slow for a huge file. I would suggest sed like this:
sed 'NUMq;d' file
Where NUM is the number of the line you want to print; so, for example, sed '10q;d' file to print the 10th line of file.
Explanation:...
Do browsers parse javascript on every page load?
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These are the details that I've been able to dig up. It's worth noting first that although JavaScript is usually considered to be interpreted and run on a VM, this isn't really the case with the modern interpreters, which tend to compile the source directly into machine code (w...
Commenting multiple lines in DOS batch file
I have written huge MS DOS Batch file. To test this batch file I need to execute some lines only and want to hide/comment out remaining.
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Objective-C: Calling selectors with multiple arguments
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Your method signature is:
- (void) myTest:(NSString *)
withAString happens to be the parameter (the name is misleading, it looks like it is part of the selector's signature).
If you call the function in this manner:
[self performSelector:@selector(myTest:) withObject:myString];
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Test if lists share any items in python
I want to check if any of the items in one list are present in another list. I can do it simply with the code below, but I suspect there might be a library function to do this. If not, is there a more pythonic method of achieving the same result.
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Get size of an Iterable in Java
I need to figure out the number of elements in an Iterable in Java.
I know I can do this:
10 Answers
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How to show the “Are you sure you want to navigate away from this page?” when changes committed?
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Modern browsers now consider displaying a custom message to be a security hazard and it has therefore been removed from all of them. Browsers now only display generic messages. Since we no longer have to worry about setting the message, it is as simple as:
// Enable navigation prompt
window.on...
Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib
When starting up my web site for the first time, I'm getting this error
10 Answers
10
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Can you change what a symlink points to after it is created?
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AFAIK, no, you can't. You have to remove it and recreate it. Actually, you can overwrite a symlink and thus update the pathname referenced by it:
$ ln -s .bashrc test
$ ls -al test
lrwxrwxrwx 1 pascal pascal 7 2009-09-23 17:12 test -> .bashrc
$ ln -s .profile te...