Tutorial by Examples: n

Since a signal handler will be called by the kernel using the C calling convention, we must tell the compiler to use the C calling convention when compiling the function. volatile sig_atomic_t death_signal = 0; extern "C" void cleanup(int signum) { death_signal = signum; } int mai...

A C library header can usually be included into a C++ program, since most declarations are valid in both C and C++. For example, consider the following foo.h: typedef struct Foo { int bar; } Foo; Foo make_foo(int); The definition of make_foo is separately compiled and distributed with the...

An explicit instantiation definition creates and declares a concrete class, function, or variable from a template, without using it just yet. An explicit instantiation can be referenced from other translation units. This can be used to avoid defining a template in a header file, if it will only be i...

import sys from PyQt4.QtCore import * from PyQt4.QtGui import * def window(): app = QApplication(sys.argv) win = QDialog() b1 = QPushButton(win) b1.setText("Button1") b1.move(50,20) b1.clicked.connect(b1_clicked) b2 = QPushButton(win) b2.setText(&quot...

let col_1 = db.collection('col_1'); let col_2 = db.collection('col_2'); col_1 .aggregate([ { $match: { "_id": 1 } }, { $lookup: { from: "col_2", localField: "id", foreignField: "id", ...

go env [var ...] prints go environment information. By default it prints all the information. $go env GOARCH="amd64" GOBIN="" GOEXE="" GOHOSTARCH="amd64" GOHOSTOS="darwin" GOOS="darwin" GOPATH="/Users/vikashkv/work" ...

retrieve all documents in a collection db.collection.find({}); retrieve documents in a collection using a condition ( similar to WHERE in MYSQL ) db.collection.find({key: value}); example db.users.find({email:"[email protected]"}); retrieve documents in a collection using Boole...

db.collection.findOne({}); the querying functionality is similar to find() but this will end execution the moment it finds one document matching its condition , if used with and empty object , it will fetch the first document and return it . findOne() mongodb api documentation

As node.js is often used to build API, proper CORS setting can be a life saver if you want to be able to request the API from different domains. In the exemple, we'll set it up for the wider configuration (authorize all request types from any domain. In your server.js after initializing express: ...

Suppose we want to write a constraint which matches a number, but approximatively. Say, you are supposed to have 95 people in a survey, but 93 or 96 will do as well. We can write a custom constraint of the form: public class AlmostEqualToConstraint : Constraint { readonly int _expected; ...

We're going to integrate the AlmostEqualToConstraint with the fluent NUnit interfaces, specifically the Is one. We'll need to extend the NUnit provided Is and use that throughout our code. public class Is : NUnit.Framework.Is { public static AlmostEqualToConstraint AlmostEqualTo(int expected,...

Users often turn up in a situation when a business process cannot be finished because the user has not entered all the necessary information. An example of this situation is when a user tries to create a drop-ship order with missing customer address. According to UX best practices, the system shou...

Note: Angular CLI versions are under rapid development. This documentation targets for the latest version. Prerequisites To execute and work with the latest version, Angular CLI and the project have dependencies that require node v6.9.0 or higher. Setup Make sure that a node version is insta...

Detailed instructions on getting adobe-analytics set up or installed.

Let's say we have some server that registers new users and greets them with some message. And we want to monitor this server and change some of it's parameters. First, we need an interface with our monitoring and control methods public interface UserCounterMBean { long getSleepTime(); ...

Let's take an scenario to understand advance function in better way, struct User { var name: String var age: Int var country: String? } //User's information let user1 = User(name: "John", age: 24, country: "USA") let user2 = User(name: "Chan", age...

The Entity Framework library comes only with an SQL Server provider. To use SQLite will require additional dependencies and configuration. All required dependencies are available on NuGet. Install SQLite Managed Libraries All of the mananged depedencies can be installed using the NuGet Package Man...

public async int call_async () { return 1; } call_async.begin ((obj, res) => { var ret = call_async.end (res); }); To call an asynchronous functions from a synchronous context, use the begin method and pass a callback to receive the result. The two arguments are: obj is a GLi...

Detailed instructions on getting webview set up or installed.

JS es6 (also known as es2015) is a set of new features to JS language aim to make it more intuitive when using OOP or while facing modern development tasks. Prerequisites: Check out the new es6 features at http://es6-features.org - it may clarify to you if you really intend to use it on your n...