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NSObject +load and +initialize - What do they do?
... can see how the runtime looks up the load method as a special case in the _class_getLoadMethod of objc-runtime-new.mm, and calls it directly from call_class_loads in objc-loadmethod.mm.
The runtime also runs the load method of every category it loads, even if several categories on the same class i...
Waiting until two async blocks are executed before starting another block
...y Programming Guide
Your example could look something like this:
dispatch_group_t group = dispatch_group_create();
dispatch_group_async(group,dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^ {
// block1
NSLog(@"Block1");
[NSThread sleepForTimeInterval:5.0];
NSLog(@"Bl...
Defining custom attrs
...mething and this is how you end up referring to it in code, e.g., R.attr.my_attribute. The format attribute can have different values depending on the 'type' of attribute you want.
reference - if it references another resource id (e.g, "@color/my_color", "@layout/my_layout")
color
boolean
dimensi...
How do you write a migration to rename an ActiveRecord model and its table in Rails?
...ameOldTableToNewTable < ActiveRecord::Migration
def self.up
rename_table :old_table_name, :new_table_name
end
def self.down
rename_table :new_table_name, :old_table_name
end
end
I had to go and rename the model declaration file manually.
Edit:
In Rails 3.1 & 4, ActiveReco...
The difference between fork(), vfork(), exec() and clone()
...all program (think Java's Runtime.exec()). POSIX has standardized the posix_spawn() to replace these latter two more modern uses of vfork().
posix_spawn() does the equivalent of a fork()/execve(), and also allows some fd juggling in between. It's supposed to replace fork()/execve(), mainly for non-M...
How to resize an image with OpenCV2.0 and Python2.6
...ll resize the image to have 100 cols (width) and 50 rows (height):
resized_image = cv2.resize(image, (100, 50))
Another option is to use scipy module, by using:
small = scipy.misc.imresize(image, 0.5)
There are obviously more options you can read in the documentation of those functions (cv2.r...
64-bit version of Boost for 64-bit windows
... it is also possible to use the stagedir parametter: "bjam --stagedir=./lib_64bit address-model=64 toolset=msvc threading=multi" and "bjam --stagedir=./lib toolset=msvc threading=multi"
– Odin
Jul 11 '12 at 15:20
...
Retargeting solution from .Net 4.0 to 4.5 - how to retarget the NuGet packages?
...nning under the Package Manager Console: get-package | % { update-package $_.Id -reinstall -ProjectName $_.ProjectName -ignoreDependencies }
– Kaleb Pederson
May 6 '16 at 19:18
...
How to publish a website made by Node.js to Github Pages?
...
@Akshat_Jiwan_Sharma You are right. That's also what I was knowing, but today I saw this site on github and thought that you can actually use Node.js. I didn't observe that it was just a repository in the organization. If it was the...
Why would I ever use push_back instead of emplace_back?
C++11 vectors have the new function emplace_back . Unlike push_back , which relies on compiler optimizations to avoid copies, emplace_back uses perfect forwarding to send the arguments directly to the constructor to create an object in-place. It seems to me that emplace_back does everything p...