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Explanation of strong and weak storage in iOS5
...lse". It's the "someone else" that is important.
Consider the following:
__strong id strongObject = <some_object>;
__weak id weakObject = strongObject;
Now we've got a two pointers to <some_object>, one strong and one weak. If we set strongObject to nil like so:
strongObject = nil;
...
Concept of void pointer in C programming
...ligned at 4-byte boundary to be dereferenced).
For example, reading uint16_t from void*:
/* may receive wrong value if ptr is not 2-byte aligned */
uint16_t value = *(uint16_t*)ptr;
/* portable way of reading a little-endian value */
uint16_t value = *(uint8_t*)ptr
| ((*((uint8_t*)...
How to loop through a plain JavaScript object with the objects as members?
...
for (var key in validation_messages) {
// skip loop if the property is from prototype
if (!validation_messages.hasOwnProperty(key)) continue;
var obj = validation_messages[key];
for (var prop in obj) {
// skip loop if the prop...
Applying a function to every row of a table using dplyr?
...f Hadley's examples using pmap:
iris %>%
mutate(Max.Len= purrr::pmap_dbl(list(Sepal.Length, Petal.Length), max))
Using this approach, you can give an arbitrary number of arguments to the function (.f) inside pmap.
pmap is a good conceptual approach because it reflects the fact that when ...
Center HTML Input Text Field Placeholder
...lder as well as the text entered into the field
– max_
Sep 11 '11 at 21:48
1
Yes. This is what th...
NSIS学习笔记（持续更新） - C/C++ - 清泛网 - 专注C/C++及内核技术
...。
#include <windows.h>
#include <pluginapi.h> // nsis plugin
HWND g_hwndParent;
// To work with Unicode version of NSIS, please use TCHAR-type
// functions for accessing the variables and the stack.
void __declspec(dllexport) myFunction(HWND hwndParent, int string_size,
TCHAR *variable...
MongoDB not equal to
...thor : 'you', post: "how to query"})
db.test.find({'post': {$ne : ""}})
{ "_id" : ObjectId("4f68b1a7768972d396fe2268"), "author" : "you", "post" : "how to query" }
And now $not, which takes in predicate ($ne) and negates it ($not):
db.test.find({'post': {$not: {$ne : ""}}})
{ "_id" : ObjectId("4f...
Interface defining a constructor signature?
...ialize<GraphicsDeviceManager>, IDrawable
{
GraphicsDeviceManager _graphicsDeviceManager;
public Drawable(GraphicsDeviceManager graphicsDeviceManager)
: base (graphicsDeviceManager)
{
_graphicsDeviceManager = graphicsDeviceManager;
}
public void Update()
...
How to get current date & time in MySQL?
...
You can use NOW():
INSERT INTO servers (server_name, online_status, exchange, disk_space, network_shares, c_time)
VALUES('m1', 'ONLINE', 'exchange', 'disk_space', 'network_shares', NOW())
share
...
Batch file to delete files older than N days
... I used this syntax on Win Server 2008: forfiles /P "C:\Mysql_backup" /S /M *.sql /D -30 /C "cmd /c del @PATH"
– jman
Apr 18 '11 at 8:42
...