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How is std::function implemented?
... dynamically. The std::function object is always of the same size and will allocate space as needed for the different functors in the heap.
In real life there are different optimizations that provide performance advantages but would complicate the answer. The type could use small object optimizatio...
What is the difference between ${var}, “$var”, and “${var}” in the Bash shell?
...happen in a particular order, and some have specific use cases.
Braces as Token Delimiters
The ${var} syntax is primarily used for delimiting ambiguous tokens. For example, consider the following:
$ var1=foo; var2=bar; var12=12
$ echo $var12
12
$ echo ${var1}2
foo2
Braces in Array Expansions
T...
#ifdef vs #if - which is better/safer as a method for enabling/disabling compilation of particular s
...rather than 0/1 in your #define, and because the value is a single lexical token, it's the one time you don't need parentheses around it.
#define DEBUG_ENABLED true
instead of
#define DEBUG_ENABLED (1)
share
...
How do you do Impersonation in .NET?
...nerally use WindowsIdentity.RunImpersonated, which accepts a handle to the token of the user account, and then either an Action or Func<T> for the code to execute.
WindowsIdentity.RunImpersonated(tokenHandle, () =>
{
// do whatever you want as this user.
});
or
var result = WindowsI...
How do I trim leading/trailing whitespace in a standard way?
... pointer to a substring of the original string.
// If the given string was allocated dynamically, the caller must not overwrite
// that pointer with the returned value, since the original pointer must be
// deallocated using the same allocator with which it was allocated. The return
// value must N...
Python List vs. Array - when to use?
...discontiguous and sparse arrays, and I think some pluggable strategies for allocating memory for large arrays... some of these advanced features will make it user less memory, while others will improve performance by using more memory.
– Dan Lenski
Oct 29 '14 a...
How to make sure that string is valid JSON using JSON.NET
...method).
(Using JSON.Net)
Simplest way would be to Parse the string using JToken.Parse, and also to check if the string starts with { or [ and ends with } or ] respectively (added from this answer):
private static bool IsValidJson(string strInput)
{
if (string.IsNullOrWhiteSpace(strInput)) { ret...
Java heap terminology: young, old and permanent generations?
...lowing.
Eden Space (heap): The pool from which memory is initially allocated
for most objects.
Survivor Space (heap): The pool containing objects that have survived
the garbage collection of the Eden
space.
Tenured Generation (heap): The pool containing objects that have existed
...
Make Https call using HttpClient
....github.com");
client.DefaultRequestHeaders.Add(
"Authorization",
"token 123456789307d8c1d138ddb0848ede028ed30567");
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.Add(
"User-Agent",
"Mozilla/5.0 (Wi...
How can a web application send push notifications to iOS devices? [closed]
...ive app is registered for push notification, it can send the authorization token to the server, which can be used in conjunction with the certificate used to provision the native client, to send the push notifications to the mobile device.
As specified in another answer, one option is to 'wrap' yo...