Tutorial by Examples: e

Semaphores are used to synchronize operations between two or more processes. POSIX defines two different sets of semaphore functions: 'System V IPC' — semctl(), semop(), semget(). 'POSIX Semaphores' — sem_close(), sem_destroy(), sem_getvalue(), sem_init(), sem_open(), sem_post(), sem_try...

Parent element html <child-component [isSelected]="inputPropValue"></child-component> Parent element ts export class AppComponent { inputPropValue: true } Child component ts: export class ChildComponent { @Input() inputPropValue = false; } Child compone...

The easiest way to connect via curl to a different server is to alter the hosts file on your machine. On Linux and Unix systems, the hosts file is located in /etc/hosts, while on Windows systems it will be located in c:\windows\system32\drivers\etc\hosts. Once you open the file with a text editor ...

The most effective way to resolve curl to a different server is to use the --resolve option. This option will insert the address into curl's DNS cache, so it will effectively make curl believe that's the address it got when it resolved the name. Like so: curl --resolve eaxmple.com:80:1.2.3.4 http:...

The "Host:" header is a normal way an HTTP client tells the HTTP server which server it speaks to. By passing custom modified "Host:" header you can have the server respond with the content of the site, even if you didn't actually connect to the host name. For example, if you ha...

Lets have the following example.bat and call it with arguments 1 ,2 and 3: @echo off ( shift shift echo %1 ) As the variable expansion will change after the the end brackets context is reached the output will be: 1 As this might be an issue when shifting inside brackets ...

from django.contrib.auth.models import User class UserAdmin(admin.ModelAdmin): list_display = ('email', 'first_name', 'last_name') list_filter = ('is_staff', 'is_superuser') admin.site.unregister(User) admin.site.register(User, UserAdmin) We need to unregister before regis...

First is first, ensure that USE_TZ = True in your settings.py file. Also set a default time zone value to TIME_ZONE such as TIME_ZONE='UTC'. View a complete list of timezones here. If USE_TZ is False, TIME_ZONE will be the time zone that Django will use to store all datetimes. When USE_TZ is enable...

Python's datetime.datetime objects have a tzinfo attribute that is used to store time zone information. When the attribute is set the object is considered Aware, when the attribute is not set it is considered a Naive. To ensure that a timezone is naive or aware, you can use .is_naive() and .is_awar...

packed is a variable attribute that is used with structures and unions in order to minimize the memory requirements. #include <stdio.h> struct foo { int a; char c; }; struct __attribute__((__packed__))foo_packed { int a; char c; }; int main() { printf("...

I wrote a simple C code foo.c int main() { int i = 0; int j = 0; for (i = 0; i < 5; i++) { j = i + 1; } return 0; } When compiled with -O0 i.e. by disabling all compiler optimizations $ gcc -o foo.S foo.c -O0 -S I got this: .file "foo.c&...

Declaring a DLL procedure to work with different VBA versions: Option Explicit #If Win64 Then Private Declare PtrSafe Sub xLib "Kernel32" Alias "Sleep" (ByVal dwMilliseconds As Long) #ElseIf Win32 Then Private Declare Sub apiSleep Lib "Kernel32" Ali...

Option Explicit #If Win64 Then 'Win64 = True, Win32 = False, Win16 = False Private Declare PtrSafe Sub apiCopyMemory Lib "Kernel32" Alias "RtlMoveMemory" (MyDest As Any, MySource As Any, ByVal MySize As Long) Private Declare PtrSafe Sub apiExitProcess Lib "Kern...

#ElseIf Win32 Then 'Win32 = True, Win16 = False Private Declare Sub apiCopyMemory Lib "Kernel32" Alias "RtlMoveMemory" (MyDest As Any, MySource As Any, ByVal MySize As Long) Private Declare Sub apiExitProcess Lib "Kernel32" Alias "ExitProcess" (ByVa...

hello_world.c #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #define AUTHOR "Bruce Lee" #define DESC "Hello World driver" static int __init init(void) { printk(KERN_DEBUG "Hello World\n"); return 0;...

var foo : Int by Delegates.observable("1") { property, oldValue, newValue -> println("${property.name} was changed from $oldValue to $newValue") } foo = 2 The example prints foo was changed from 1 to 2

val map = mapOf("foo" to 1) val foo : String by map println(foo) The example prints 1

class MyDelegate { operator fun getValue(owner: Any?, property: KProperty<*>): String { return "Delegated value" } } val foo : String by MyDelegate() println(foo) The example prints Delegated value

interface Foo { fun example() } class Bar { fun example() { println("Hello, world!") } } class Baz(b : Bar) : Foo by b Baz(Bar()).example() The example prints Hello, world!

val a = arrayOf(1, 2, 3) // creates an Array<Int> of size 3 containing [1, 2, 3].