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Set environment variables on Mac OS X Lion
...ble you set in your .bash_profile will only affect your bash shells.
Generally I only set variables in my .bash_profile file and don't change the .plist file (or launchd file on Mavericks). Most OS X windowed applications don't need any custom environment. Only when an application actually needs a ...
Is it safe to use -1 to set all bits to true?
...s one:
unsigned long a = ~0u;
It won't necessarily store a pattern with all bits 1 into a. But it will first create a pattern with all bits 1 in an unsigned int, and then assign it to a. What happens when unsigned long has more bits is that not all of those are 1.
And consider this one, which wi...
Is it possible to serialize and deserialize a class in C++?
...e it, here.
The only native way to do it is to use streams. That's essentially all the Boost::serialization library does, it extends the stream method by setting up a framework to write objects to a text-like format and read them from the same format.
For built-in types, or your own types with op...
Python date string to date object
....strptime("2015-02-24T13:00:00-08:00", "%Y-%B-%dT%H:%M:%S-%H:%M").date()
and you get:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/_strptime.py", line 308, in _strptime
format_regex = _TimeRE_cache.compile(format)
File...
Async image loading from url inside a UITableView cell - image changes to wrong image while scrollin
...se you'll see the flickering of images.
A more subtle issue is that on a really slow network, your asynchronous request might not finish before the cell scrolls off the screen. You can use the UITableView method cellForRowAtIndexPath: (not to be confused with the similarly named UITableViewDataSourc...
jQuery - Detect value change on hidden input field
...es across this thread.
Changes in value to hidden elements don't automatically fire the .change() event. So, wherever it is that you're setting that value, you also have to tell jQuery to trigger it.
function setUserID(myValue) {
$('#userid').val(myValue)
.trigger('change');...
What is an xs:NCName type and when should it be used?
...s, then they are NCNames.
xs:string puts no restrictions on your names at all, but xs:NCName basically disallows ":" to appear in the string.
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Why is reading lines from stdin much slower in C++ than Python?
...tl;dr: Because of different default settings in C++ requiring more system calls.
By default, cin is synchronized with stdio, which causes it to avoid any input buffering. If you add this to the top of your main, you should see much better performance:
std::ios_base::sync_with_stdio(false);
Normall...
c++获取windows程序的版本号 - C/C++ - 清泛网 - 专注C/C++及内核技术
... // Get the version information size for allocate the buffer
DWORD dwHandle;
DWORD dwDataSize = ::GetFileVersionInfoSize((LPTSTR)lpszModuleName, &dwHandle);
if ( dwDataSize == 0 )
return FALSE;
// Allocate buffer and retrieve version information
LPBYTE lpVersion...
How to empty a list?
...
This actually removes the contents from the list, but doesn't replace the old label with a new empty list:
del lst[:]
Here's an example:
lst1 = [1, 2, 3]
lst2 = lst1
del lst1[:]
print(lst2)
For the sake of completeness, the slic...