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How do you concatenate Lists in C#?
...working fine I think so. As previously said, Concat returns a new sequence and while converting the result to List, it does the job perfectly.
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PHP: How to check if image file exists?
.../'.$filename)) {
… }
Also, make sure $filename is properly validated. And then, it will only work when allow_url_fopen is activated in your PHP config
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How efficient is locking an unlocked mutex? What is the cost of a mutex?
...bunch of mutexes or a single one for an object.
If you have many threads and the access to the object happens often, then multiple locks would increase parallelism. At the cost of maintainability, since more locking means more debugging of the locking.
How efficient is it to lock a mutex? I.e....
Is there a way to instantiate objects from a string holding their class name?
...<DerivedA>;
map["DerivedB"] = &createInstance<DerivedB>;
And then you can do
return map[some_string]();
Getting a new instance. Another idea is to have the types register themself:
// in base.hpp:
template<typename T> Base * createT() { return new T; }
struct BaseFactor...
'IF' in 'SELECT' statement - choose output value based on column values
I need amount to be amount if report.type='P' and -amount if report.type='N' . How do I add this to the above query?
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Nullable type as a generic parameter possible?
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Change the return type to Nullable<T>, and call the method with the non nullable parameter
static void Main(string[] args)
{
int? i = GetValueOrNull<int>(null, string.Empty);
}
public static Nullable<T> GetValueOrNull<T>(DbDataRecord reader...
Characters allowed in a URL
... used within a GET without being encoded? At the moment I am using A-Z a-z and 0-9... but I am looking to find out the full list.
...
Parse a URI String into Name-Value Collection
...till quite popular, I made an improved version of the method above, which handles multiple parameters with the same key and parameters with no value as well.
public static Map<String, List<String>> splitQuery(URL url) throws UnsupportedEncodingException {
final Map<String, List<S...
Why aren't pointers initialized with NULL by default?
...
We all realize that pointer (and other POD types) should be initialized.
The question then becomes 'who should initialize them'.
Well there are basically two methods:
The compiler initializes them.
The developer initializes them.
Let us assume tha...
ZeroMQ的学习和研究（PHP代码实例） - C/C++ - 清泛网 - 专注C/C++及内核技术
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* Weather update server
* Binds PUB socket to tcp://*:5556
* Publishes random weather updates
* @author Ian Barber <ian (dot) barber (at) gmail (dot) com>
*/
// Prepare our context and publisher
$context = new ZMQContext ();
$publisher = $context->getSocket (ZMQ::SOCKET_PUB);
$publisher-...