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What is “:-!!” in C code?
... effect, a way to check whether the expression e can be evaluated to be 0, and if not, to fail the build.
The macro is somewhat misnamed; it should be something more like BUILD_BUG_OR_ZERO, rather than ...ON_ZERO. (There have been occasional discussions about whether this is a confusing name.)
You...
Call a python function from jinja2
I am using jinja2, and I want to call a python function as a helper, using a similar syntax as if I were calling a macro. jinja2 seems intent on preventing me from making a function call, and insists I repeat myself by copying the function into a template as a macro.
...
`staticmethod` and `abc.abstractmethod`: Will it blend?
In my Python app I want to make a method that is both a staticmethod and an abc.abstractmethod . How do I do this?
4 Ans...
Android Studio with Google Play Services
I'm trying to test Google Play Services with the new Android Studio.
I have a project with a dependency to the google_play_services.jar.
But when I try to Rebuild the project I get the following errors:
...
How to remove a key from a Python dictionary?
...y', None)
This will return my_dict[key] if key exists in the dictionary, and None otherwise. If the second parameter is not specified (ie. my_dict.pop('key')) and key does not exist, a KeyError is raised.
To delete a key that is guaranteed to exist, you can also use
del my_dict['key']
This wil...
What is the difference between the kernel space and the user space?
What is the difference between the kernel space and the user space? Do kernel space, kernel threads, kernel processes and kernel stack mean the same thing? Also, why do we need this differentiation?
...
Python in Xcode 4+?
...Other” in the left pane, then "External Build System" in the right page, and next click "Next".
Enter the product name, organization name, or organization identifier.
For the “Build Tool” field, type in /usr/local/bin/python3 for Python 3 or /usr/bin/python for Python 2 and then click “Next...
What command means “do nothing” in a conditional in Bash?
...
The no-op command in shell is : (colon).
if [ "$a" -ge 10 ]
then
:
elif [ "$a" -le 5 ]
then
echo "1"
else
echo "2"
fi
From the bash manual:
: (a colon)
Do nothing beyond expanding arguments and performing redirections....
jquery input select all on focus
I'm using this code to try and select all of the text in the field when a user focuses on the field. What happens is, it selects all for a second, then its unselected and the typing cursor is left where I clicked...
...
BigDecimal setScale and round
...lluded to but not directly addressed is the difference between "precision" and "scale" and how they are used in the two statements. "precision" is the total number of significant digits in a number. "scale" is the number of digits to the right of the decimal point.
The MathContext constructor onl...