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Why do I get a segmentation fault when writing to a “char *s” initialized with a string literal, but
...shes if I try to assign a new value to p[i].
A: A string literal (the formal term
for a double-quoted string in C
source) can be used in two slightly
different ways:
As the initializer for an array of char, as in the declaration of char a[] , it specifies the initial values
of t...
Ruby: require vs require_relative - best practice to workaround running in both Ruby =1.
...
A workaround for this was just added to the 'aws' gem so thought I'd share as it was inspired by this post.
https://github.com/appoxy/aws/blob/master/lib/awsbase/require_relative.rb
unless Kernel.respond_to?(:require_relative)
module...
pydot and graphviz error: Couldn't import dot_parser, loading of dot files will not be possible
...
Answer for pydot >= 1.1:
The incompatibility of (upstream) pydot has been fixed by 6dff94b3f1, and thus pydot >= 1.1 will be compatible with pyparsing >= 1.5.7.
Answer applicable to pydot <= 1.0.28:
For anyone else ...
How do I get current date/time on the Windows command line in a suitable format for usage in a file/
Update: Now that it's 2016 I'd use PowerShell for this unless there's a really compelling backwards-compatible reason for it, particularly because of the regional settings issue with using date . See @npocmaka's https://stackoverflow.com/a/19799236/8479
...
printf format specifiers for uint32_t and size_t
...e right thing. Just because int32_t happens to be int on your compiler/platform doesn't mean it might not be long on another. Same for size_t. It's actually going out of its way and doing more work to detect this portability bug since the easy, natural check would be to just honor the typedef like t...
What does |= (ior) do in Python?
...
|= performs an in-place+ operation between pairs of objects. In particular, between:
sets: a union operation
dicts: an update operation
counters: a union (of multisets) operation
numbers: a bitwise OR, binary operation
In most c...
What is the _snowman param in Ruby on Rails 3 forms for?
In Ruby on Rails 3 (currently using Beta 4), I see that when using the form_tag or form_for helpers there is a hidden field named _snowman with the value of ☃ ( Unicode \x9731) showing up.
...
What does the PHP error message “Notice: Use of undefined constant” mean?
...age = mysql_real_escape_string($_POST['message']);
As is, it was looking for constants called department, name, email, message, etc. When it doesn't find such a constant, PHP (bizarrely) interprets it as a string ('department', etc). Obviously, this can easily break if you do defined such a cons...
Reference: What is variable scope, which variables are accessible from where and what are “undefined
...included code as applies to any other code: only functions separate scope. For the purpose of scope, you may think of including files like copy and pasting code:
c.php
<?php
function myFunc() {
include 'a.php';
echo $foo; // works
}
myFunc();
echo $foo; // doesn't work!
In the a...
Can I create links with 'target=“_blank”' in Markdown?
...ld!</a>
Most Markdown engines I've seen allow plain old HTML, just for situations like this where a generic text markup system just won't cut it. (The StackOverflow engine, for example.) They then run the entire output through an HTML whitelist filter, regardless, since even a Markdown-only ...