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C++对象布局及多态探索之菱形结构虚继承 - C/C++ - 清泛网 - 专注C/C++及内核技术
...0则从C100和C101多重继承而来。
struct C041
{
C041() : c_(0x01) {}
virtual void foo() { c_ = 0x02; }
char c_;
};
struct C100 : public virtual C041
{
C100() : c_(0x02) {}
char c_;
};
struct C101 : public virtual C041
{
C101() : c_(0x03) {}
...
java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F…'
...ead:
For a supplementary character, utf8 cannot store the character at all,
while utf8mb4 requires four bytes to store it. Since utf8 cannot store
the character at all, you do not have any supplementary characters in
utf8 columns and you need not worry about converting characters or
losi...
Convert Base64 string to an image file? [duplicate]
... data in the function before decoding the string, like so.
function base64_to_jpeg($base64_string, $output_file) {
// open the output file for writing
$ifp = fopen( $output_file, 'wb' );
// split the string on commas
// $data[ 0 ] == "data:image/png;base64"
// $data[ 1 ] == &l...
How do I pass extra arguments to a Python decorator?
... it needs to return another function which is the actual decorator:
def my_decorator(param):
def actual_decorator(func):
print("Decorating function {}, with parameter {}".format(func.__name__, param))
return function_wrapper(func) # assume we defined a wrapper somewhere
ret...
Python Flask, how to set content type
...
Try like this:
from flask import Response
@app.route('/ajax_ddl')
def ajax_ddl():
xml = 'foo'
return Response(xml, mimetype='text/xml')
The actual Content-Type is based on the mimetype parameter and the charset (defaults to UTF-8).
Response (and request) objects are docume...
Handling applicationDidBecomeActive - “How can a view controller respond to the app becoming Active?
...tionDidBecomeActiveNotification and specify which method that you want to call when that notification gets sent to your application.
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(someMethod:)
...
When to use symbols instead of strings in Ruby?
...iers. For Ruby < 2.2 only use symbols when they aren't generated dynamically, to avoid memory leaks.
Full answer
The only reason not to use them for identifiers that are generated dynamically is because of memory concerns.
This question is very common because many programming languages don't h...
To ARC or not to ARC? What are the pros and cons? [closed]
...t has no GC runtime overhead. The compiler inserts retains and releases in all the places you should have anyway. But it's smarter than you and can optimize out the ones that aren't actually needed (just like it can unroll loops, eliminate temporary variables, inline functions, etc.)
OK, now I will...
Which is faster in Python: x**.5 or math.sqrt(x)?
...
I've now run it 3 times on codepad.org and all three times a() was much faster than b().
– Jeremy Ruten
Nov 29 '08 at 1:38
13
...
Can I replace groups in Java regex?
I have this code, and I want to know, if I can replace only groups (not all pattern) in Java regex.
Code:
7 Answers
...