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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 should one use std::optional?
...std::string s, int& i);
Another way that this could be done is especially bad:
int* try_parse_int(std::string s); //return nullptr if fail
This requires dynamic memory allocation, worrying about ownership, etc. - always prefer one of the other two signatures above.
Another example:
clas...
Nodejs send file in response
... util.pump is gone and was replaced with a method on the Stream prototype called pipe; the code below reflects this.
var http = require('http'),
fileSystem = require('fs'),
path = require('path');
http.createServer(function(request, response) {
var filePath = path.join(__dirname, 'myfi...
Post JSON using Python Requests
... |
edited Oct 19 '19 at 10:32
Keithel
8566 bronze badges
answered Oct 13 '14 at 16:08
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What is the difference between Cygwin and MinGW?
...Unix-based applications to Windows much easier, by emulating many of the small details that Unix-based operating systems provide, and are documented by the POSIX standards. Your application can use Unix feature such as pipes, Unix-style file and directory access, and so forth, and it can be compile...
When should use Readonly and Get only properties
...Fuel; // Will work
f.Fuel = a; // Does not compile
f.FillFuelTank(10); // Value is changed from the method's code
}
Setting the private field of your class as readonly allows you to set the field value only once (using an inline assignment or in the class constructor).
You will not be abl...
Detect if the app was launched/opened from a push notification
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I am getting the call to application:didReceiveRemoteNotification: after tapping the notification regardless of whether the app is just in the background or not running at all so this answer suits my needs perfectly. Tested on iOS 7 & 8
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How can I reliably get an object's address when operator& is overloaded?
...argument and returning no result. This reference to a function can be trivially converted into a pointer to function -- from @Konstantin: According to 13.3.3.2 both T & and T * are indistinguishable for functions. The 1st one is an Identity conversion and the 2nd one is Function-to-Pointer conve...
Why git can't remember my passphrase under Windows
...msysgit or not.
First solution Assumes Windows, msysgit, and PuTTY.
Install msysgit and PuTTY as instructed.
(Optional) Add PuTTY to your path. (If you do not do this, then any references to PuTTY commands below must be prefixed with the full path to the appropriate executable.)
If you have not d...
How to convert a string from uppercase to lowercase in Bash? [duplicate]
...ing to find a way to convert a string value from upper case to lower case. All the search results show approaches of using tr command.
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