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Creating the Singleton design pattern in PHP5
...nstance();
$fact == $fact2;
But:
$fact = new UserFactory()
Throws an error.
See http://php.net/manual/en/language.variables.scope.php#language.variables.scope.static to understand static variable scopes and why setting static $inst = null; works.
...
Can a class member function template be virtual?
... like this:
X x;
x.func2<string>("X x");
g++ report the following error:
vtempl.cpp:34: error: invalid use of `virtual' in template declaration of `virtu
al void X::func2(const T&)'
So it is obvious that:
virtual member function can be used in a class template. It is easy for compi...
Swift - Split string over multiple lines
...te and the +, otherwise you'll get a "'+' is not a postfix unary operator" error
– Orlin Georgiev
Apr 7 '15 at 8:20
Th...
Awaiting multiple Tasks with different results
...stion is whether you want to await them one at a time or all together. The error handling is slightly different - if you use Task.WhenAll, then it will await them all, even if one of them fails early.
– Stephen Cleary
Mar 13 '15 at 12:17
...
What is the equivalent of Java's final in C#?
...e - failing to assign V or assigning V two or more times will result in an error.
C#'s readonly keyword has no such guarantee - the compiler is more than happy to leave readonly members unassigned or allow you to assign them multiple times within a constructor.
So, final and readonly (at least wit...
Version number comparison in Python
...e this solution to solve the same problem at the Leetcode problem I get an error at the while loop saying "list index out of range". Can you please help why that occurs? Here is the problem : leetcode.com/explore/interview/card/amazon/76/array-and-strings/…
– YouHaveaBigEgo
...
Downloading a file from spring controllers
... response.flushBuffer();
} catch (IOException ex) {
log.info("Error writing file to output stream. Filename was '{}'", fileName, ex);
throw new RuntimeException("IOError writing file to output stream");
}
}
Generally speaking, when you have response.getOutputStream(), you c...
Is 0 a decimal literal or an octal literal?
...l literal could be interpreted as a decimal literal. I can see the compile error, now: ERROR: 0 is ambiguous, could be octal zero or could be decimal zero. Consider using (1 - 1) to disambiguate.
– CB Bailey
Aug 1 '11 at 9:25
...
How do I implement a callback in PHP?
... be called directly
$cb2 = 'ClassName::someStaticMethod';
$cb2(); // fatal error
// legacy syntax for PHP 4
$cb3 = array(&$object, 'somePublicMethod');
This is a safe way to use callable values in general:
if (is_callable($cb2)) {
// Autoloading will be invoked to load the class "ClassNa...
Pointer arithmetic for void pointer in C
... MSVC) disallow arithmetic on void*, and GCC disallows it if the -pedantic-errors flag is specified, or if the -Werror-pointer-arith flag is specified (this flag is useful if your code base must also compile with MSVC).
The C Standard Speaks
Quotes are taken from the n1256 draft.
The standard's d...