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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 you run GUI applications in a Docker container?
...
the creackfirefox-vnc image fails with error: Enter VNC password: stty: standard input: Inappropriate ioctl for device fgets: No such file or directory stty: standard input: Inappropriate ioctl for device x11vnc -usepw: could not find a password to use.
...
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...
How does a “stack overflow” occur and how do you prevent it?
...nded. Intentional cycles and recursion need to be artificially checked to error out if they call each other too many times.
Beyond good programming practices, static and dynamic testing, there's not much you can do on these high level systems.
Embedded systems
In the embedded world, especially i...
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...
Is it correct to use alt tag for an anchor link?
...e that the src attribute isn’t allowed either.
By validating your HTML, errors like these are reported to you.
Note that the above is for HTML5, which is W3C’s HTML standard from 2014. In 2016, HTML 5.1 became the next HTML standard. Finding the allowed attributes works in the same way. You...
Installing Latest version of git in ubuntu
...The question was what to do when the first command fails showing the above error
– Arjun Krishna P R
Oct 1 '13 at 7:54
...
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...
Unix command to find lines common in two files
...ve the temporary files afterwards, and cope with cleaning up in case of an error. In many scenarios, the process substitution will also be a lot quicker because you can avoid the disk I/O as long as the results fit into memory.
– tripleee
Dec 8 '17 at 5:41
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