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C++ Dynamic Shared Library on Linux
...were for a plugin system, you would use MyClass as a base class and define all the required functions virtual. The plugin author would then derive from MyClass, override the virtuals and implement create_object and destroy_object. Your main application would not need to be changed in any way.
...
How can I initialize base class member variables in derived class constructor?
...ince it would destroy encapsulation. Instead, create a constructor in A to allow B (or any subclass of A) to initialize them:
class A
{
protected:
A(int a, int b) : a(a), b(b) {} // Accessible to derived classes
// Change "protected" to "public" to allow others to instantiate A.
private:
...
What's the easiest way to escape HTML in Python?
...
< to &lt;
> to &gt;
& to &amp;
That is enough for all HTML.
EDIT: If you have non-ascii chars you also want to escape, for inclusion in another encoded document that uses a different encoding, like Craig says, just use:
data.encode('ascii', 'xmlcharrefreplace')
Don't for...
What's wrong with nullable columns in composite primary keys?
...
Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key containing NULL would not work.
Additonally, NULL is al...
Android: Difference between onInterceptTouchEvent and dispatchTouchEvent?
... are woefully inadequate about explaining this.
dispatchTouchEvent is actually defined on Activity, View and ViewGroup. Think of it as a controller which decides how to route the touch events.
For example, the simplest case is that of View.dispatchTouchEvent which will route the touch event to ei...
How to get a JavaScript object's class?
...
ES5 has aditionally Object.getPrototypeOf()
– Christoph
Aug 8 '09 at 18:52
29
...
Are nested try/except blocks in python a good programming practice?
...EAFP.
Personally, I prefer to avoid nesting when it's not necessary:
def __getattribute__(self, item):
try:
return object.__getattribute__(item)
except AttributeError:
pass # fallback to dict
try:
return self.dict[item]
except KeyError:
raise Attrib...
Total memory used by Python process?
...os
import psutil
process = psutil.Process(os.getpid())
print(process.memory_info().rss) # in bytes
On my current Python 2.7 install with psutil 5.6.3, the last line should be
print(process.memory_info()[0])
instead (there was a change in the API).
Note: do pip install psutil if it is not in...
Encode String to UTF-8
...
Technically speaking, byte[] doesn't have any encoding. Byte array PLUS encoding can give you string though.
– Peter Štibraný
Apr 20 '11 at 14:34
...
UILabel with text of two different colors
...ike this:
NSMutableAttributedString *text =
[[NSMutableAttributedString alloc]
initWithAttributedString: label.attributedText];
[text addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:NSMakeRange(10, 1)];
[label setAttributedText: text];
...