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NSInvocation for Dummies?
...oncept of messages is central to the objective-c philosophy. Any time you call a method, or access a variable of some object, you are sending it a message. NSInvocation comes in handy when you want to send a message to an object at a different point in time, or send the same message several times. N...
Run a single migration file
...f the ruby file:
rails console
>> require "db/migrate/20090408054532_add_foos.rb"
>> AddFoos.up
Note: newer versions of rails may require AddFoos.new.up rather than AddFoos.up.
An alternative way (without IRB) which relies on the fact that require returns an array of class names:
sc...
Run command on the Ansible host
...
Yes, you can run commands on the Ansible host. You can specify that all tasks in a play run on the Ansible host, or you can mark individual tasks to run on the Ansible host.
If you want to run an entire play on the Ansible host, then specify hosts: 127.0.0.1 and connection:local in the play,...
Should I compile with /MD or /MT?
...
By dynamically linking with /MD,
you are exposed to system updates (for good or ill),
your executable can be smaller (since it doesn't have the library embedded in it), and
I believe that at very least the code segment of a DLL is...
Remove empty elements from an array in Javascript
...ll return you a new array with the elements that pass the criteria of the callback function you provide to it.
For example, if you want to remove null or undefined values:
var array = [0, 1, null, 2, "", 3, undefined, 3,,,,,, 4,, 4,, 5,, 6,,,,];
var filtered = array.filter(function (el) {
...
How do you iterate through every file/directory recursively in standard C++?
...e to the standard.
An example, taken straight from the website:
bool find_file( const path & dir_path, // in this directory,
const std::string & file_name, // search for this name,
path & path_found ) // placing path here if found
{
...
Binding a WPF ComboBox to a custom list
...0">
<Grid>
<StackPanel>
<Button Click="Button_Click">asdf</Button>
<ComboBox ItemsSource="{Binding Path=PhonebookEntries}"
DisplayMemberPath="Name"
SelectedValuePath="Name"
SelectedValue="{Binding...
Programmatically set the initial view controller using Storyboards
How do I programmatically set the InitialViewController for a Storyboard? I want to open my storyboard to a different view depending on some condition which may vary from launch to launch.
...
Why does volatile exist?
...ed 16 bit value as a semaphore to know when the other guy was done. Essentially we did this:
void waitForSemaphore()
{
volatile uint16_t* semPtr = WELL_KNOWN_SEM_ADDR;/*well known address to my semaphore*/
while ((*semPtr) != IS_OK_FOR_ME_TO_PROCEED);
}
Without volatile, the optimizer sees ...
What's the difference between ES6 Map and WeakMap?
...e: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WeakMap):
Keys of WeakMaps are of the type Object only. Primitive data types as
keys are not allowed (e.g. a Symbol can't be a WeakMap key).
Nor can a string, number, or boolean be used as a WeakMap key. A M...