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IOCTL Linux device driver [closed]

...l, which means "input-output control" is a kind of device-specific system call. There are only a few system calls in Linux (300-400), which are not enough to express all the unique functions devices may have. So a driver can define an ioctl which allows a userspace application to send it orders. How...
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Calling C++ class methods via a function pointer

...ility with member pointers - Visual C++, at least in the past, needed some extra clues about how to represent member pointer types. I'd use the static function approach for an embedded system - the representation of a pointer is the same as any other function pointer, the costs are obvious, and ther...
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What does “not run” mean in R help pages?

...run{} for text that should only be shown, but not run, and \dontshow{} for extra commands for testing that should not be shown to users, but will be run by example() When you build a package then all code in \dontrun{} closure is visible in help as ## Not run: ... ## End(**Not run**) edit: Thi...
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What's the difference between using CGFloat and float?

I tend to use CGFloat all over the place, but I wonder if I get a senseless "performance hit" with this. CGFloat seems to be something "heavier" than float, right? At which points should I use CGFloat, and what makes really the difference? ...
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Return a value if no rows are found in Microsoft tSQL

... S.Id = @SiteId and S.Status = 1 AND (S.WebUserId = @WebUserId OR S.AllowUploads = 1) share | improve this answer | follow | ...
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Bash if statement with multiple conditions throws an error

... can use either [[ or (( keyword. When you use [[ keyword, you have to use string operators such as -eq, -lt. I think, (( is most preferred for arithmetic, because you can directly use operators such as ==, < and >. Using [[ operator a=$1 b=$2 if [[ a -eq 1 || b -eq 2 ]] || [[ a -eq 3 &&...
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How to prevent Browser cache for php site

...e in production enviroment // Functions function get_cache_prevent_string( $always = false ) { return (DEBUGGING || $always) ? date('_Y-m-d_H:i:s') : ""; } ?> <!-- ... --> <link rel="stylesheet" type="text/css" href="style.css?version=3.2<?php echo get_cache_preven...
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Python Sets vs Lists

...move the object creation now. The setup phase of the timeit loops is only called once (docs.python.org/2/library/timeit.html#timeit.Timer.timeit). – Ellis Percival Sep 30 '14 at 10:09 ...
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YouTube Video Embedded via iframe Ignoring z-index?

... @Dan, see my edit... you might already have a query string in your youtube embed code. (like ?rel=0 to not show relevant videos). If that's the case use &wmode=transparent (or opaque - I've heard opaque uses less system resources, so I use that mainly, unless I have a re...
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Using PUT method in HTML form

... XHTML 1.x forms only support GET and POST. GET and POST are the only allowed values for the "method" attribute. share | improve this answer | follow | ...