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#define macro for debug printing in C?
.... } while (0) idiom ensures that the code acts like a statement (function call). The unconditional use of the code ensures that the compiler always checks that your debug code is valid — but the optimizer will remove the code when DEBUG is 0.
If you want to work with #ifdef DEBUG, then change th...
How to make rpm auto install dependencies
...hip and filesystem permissions:
# chown -R root.root /home/user/repo
Install the createrepo package if not installed yet, and run
# createrepo /home/user/repo
# chmod -R o-w+r /home/user/repo
Create a repository configuration file, e.g. /etc/yum.repos.d/myrepo.repo containing
[local]
name=My Aw...
How to invoke the super constructor in Python?
In all other languages I've worked with the super constructor is invoked implicitly. How does one invoke it in Python? I would expect super(self) but this doesn't work.
...
How do JavaScript closures work?
...clared outside the function, regardless of when and where the function is called.
If a function was called by a function, which in turn was called by another function, then a chain of references to outer lexical environments is created. This chain is called the scope chain.
In the following code, in...
In Python, how do I determine if an object is iterable?
...e a method like isiterable ? The only solution I have found so far is to call
21 Answers
...
What would a “frozen dict” be?
...).
The most common reason to want such a type is when memoizing function calls for functions with unknown arguments. The most common solution to store a hashable equivalent of a dict (where the values are hashable) is something like tuple(sorted(kwargs.iteritems())).
This depends on the sorting n...
How to assign colors to categorical variables in ggplot2 that have stable mapping?
...maintain consistent color schemes across multiple data frames that are not all obtained by subsetting a single large data frame. Managing the factors levels in multiple data frames can become tedious if they are being pulled from separate files and not all factor levels appear in each file.
One way...
How to get the client IP address in PHP [duplicate]
...se addresses are larger than the older IPv4 addresses.
(Note that IPv6 usually uses 39 characters at most but there is also a special IPv6 notation for IPv4 addresses which in its full form can be up to 45 characters. So if you know what you are doing you can use 39 characters, but if you just want...
Python class inherits object
... so are numerous, to list some of them:
Support for descriptors. Specifically, the following constructs are made possible with descriptors:
classmethod: A method that receives the class as an implicit argument instead of the instance.
staticmethod: A method that does not receive the implicit ar...
How to watch for array changes?
...ent
}
return n;
}
});
1 Alternatively, if you'd like to target all arrays, you could override Array.prototype.push(). Use caution, though; other code in your environment may not like or expect that kind of modification. Still, if a catch-all sounds appealing, just replace myArray with Ar...