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Throw an error in a MySQL trigger
...cat('MyTriggerError: Trying to insert a negative value in trigger_test: ', cast(new.id as char));
signal sqlstate '45000' set message_text = msg;
end if;
end
//
delimiter ;
-- run the following as seperate statements:
insert into trigger_test values (1), (-1), (2); -- everything fails a...
How to check if a process id (PID) exists
...will have a race condition.
If you want to ignore the text output of kill and do something based on the exit code, you can
if ! kill $pid > /dev/null 2>&1; then
echo "Could not send SIGTERM to process $pid" >&2
fi
...
What does “for” attribute do in HTML tag?
...
The <label> tag allows you to click on the label, and it will be treated like clicking on the associated input element. There are two ways to create this association:
One way is to wrap the label element around the input element:
<label>Input here:
<input type...
Convert PDF to image with high resolution
I'm trying to use the command line program convert to take a PDF into an image (JPEG or PNG). Here is one of the PDFs that I'm trying to convert.
...
How can I mask a UIImageView?
...! But i have two troubles : Warning on "kCGImageAlphaPremultipliedLast" (i cast to "CGBitmapInfo" for fix it) AND does not work for retina images !! can you help me ??...
– fingerup
Apr 21 '15 at 9:14
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Android studio using > 100% CPU at all times - no background processes appear to be running
I've noticed Android Studio (when running) uses greater than 100% CPU at all times, even when it appears there are no background processes that the IDE is running (indexing, etc). I might suspect this were something specific to my box, but some fellow developers are encountering this as well.
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Does the default constructor initialize built-in types?
...The behavior of () initializer is different in some respects between C++98 and C++03, but not in this case. For the above class C it will be the same: () initializer performs zero initialization of C::x.
Another example of initialization that is performed without involving constructor is, of course...
How can I make a Python script standalone executable to run without ANY dependency?
I'm building a Python application and don't want to force my clients to install Python and modules.
19 Answers
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How to Implement Custom Table View Section Headers and Footers with Storyboard
...ue id and viewForHeaderInSection you can dequeue the cell with that ID and cast it to a UIView.
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Remove insignificant trailing zeros from a number?
...55555).toFixed(2);
//-> "4.56"
(4).toFixed(2);
//-> "4.00"
If you cast the return value to a number, those trailing zeroes will be dropped. This is a simpler approach than doing your own rounding or truncation math.
+(4.55555).toFixed(2);
//-> 4.56
+(4).toFixed(2);
//-> 4
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