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How efficient is locking an unlocked mutex? What is the cost of a mutex?
...ange of the flag is just few instructions and normally done without system call. If mutex is locked, syscall will happen to add the calling thread into wait queue and start the waiting. Unlocking, if the wait queue is empty, is cheap but otherwise needs a syscall to wake up one of the waiting proces...
type object 'datetime.datetime' has no attribute 'datetime'
... # as you imported the type, not the module
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: type object 'datetime.datetime' has no attribute 'datetime'
>>> datetime(2001,5,1)
datetime.datetime(2001, 5, 1, 0, 0)
I suspect you or ...
Temporarily disable some plugins using pathogen in vim.
...not in GVim, so disable it if no GUI is running
if !has('gui_running')
call add(g:pathogen_disabled, 'csscolor')
endif
" Gundo requires at least vim 7.3
if v:version < '703' || !has('python')
call add(g:pathogen_disabled, 'gundo')
endif
if v:version < '702'
call add(g:pathogen_di...
Clearing localStorage in javascript?
...
I call localStorage.clear() when my app starts up, but even if I close the browser, clear cache, etc., the data are still there. I know this because I have set an "instance" property on my model to a random number on initializ...
How to get first record in each group using Linq
...
@rogersillito that's why it's called a query (Language Integrated Query - LINQ), also the GroupBy has many overloads but there are just a few being commonly used, also it depends on the personal preference, such as some ones prefer to write it as .GroupBy...
Which characters are valid in CSS class names/selectors?
...
You can check directly at the CSS grammar.
Basically1, a name must begin with an underscore (_), a hyphen (-), or a letter(a–z), followed by any number of hyphens, underscores, letters, or numbers. There is a catch: if the first character is a hyphen, the second charact...
What is the best way to remove accents (normalize) in a Python unicode string?
...s of characters that are available. Do we really need the unicode function call in there with python 3 though? I think a tighter regex in place of the find would avoid all the trouble mentioned in the comment above, and also, memoization would help performance when it's a critical code
Correct use of flush() in JPA/Hibernate
...atabase, often until you actually commit the transaction.
For example, you call em.persist(), Hibernate remembers it has to make a database INSERT, but does not actually execute the instruction until you commit the transaction. Afaik, this is mainly done for performance reasons.
In some cases anywa...
HTML if image is not found
...ad, then I suggest using a server-side technology to serve up your images, called using a similar format to:
<img src="ImageHandler.aspx?Img=Blue.jpg" alt="I am a picture" />
In the ImageHandler.aspx code, catch any file-not-found errors and serve up your default.jpg instead.
...
text-overflow:ellipsis in Firefox 4? (and FF5)
...ntent = $i.html();
$c.empty().html(content);
}
}
It would be called like:
$(function(){
ellipsify($('#test'));
});
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