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When and why will a compiler initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?
...----- -------- -------------------------
0xCD Clean Memory Allocated memory via malloc or new but never
written by the application.
0xDD Dead Memory Memory that has been released with delete or free.
It is used to detect w...
Zoom in on a point (using scale and translate)
...-(zoomPointX * scalechange);
offsetY = -(zoomPointY * scalechange);
So really you can just pan over down and to the right when you zoom in, by a factor of how much you zoomed in, relative to the point you zoomed at.
shar...
使用App Inventor 2 控制物联网设备/低功耗蓝牙设备(BLE) · App Inventor 2 中文网
...hyay, D., & Sen, J. (2011). Internet of things: Applications and challenges in technology and standardization. Wireless Personal Communications, 58(1), 4969.
[2] Wolber, D., Abelson, H., Spertus, E., & Looney, L. (2011). App Inventor. ” O’Reilly Media, Inc.”.
[3] Macke...
How to read a text file reversely with iterator in C#
...o process from bottom up. How can I use iterator (yield return) here? Basically I don't like to load everything in memory. I know it is more efficient to use iterator in .NET.
...
What is the difference between :first-child and :first-of-type?
...first child of the parent. So far the child elements we're looking at have all been divs, but bear with me, I'll get to that in a bit.
For now, the converse also holds true: any :first-child is also :first-of-type by necessity. Since the first child here is also the first div, it will match both ps...
When splitting an empty string in Python, why does split() return an empty list while split('\n') re
...ncorporates both splitting algorithms in the same tool.
People seem to mentally model field-splitting
as a single concept even though more than one algorithm is involved.
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Can dplyr package be used for conditional mutating?
...and the conditions (except for the default value of NA at the end) are mutually exclusive, as is the case in the question, then we can use an arithmetic expression such that each term is multiplied by the desired result using na_if at the end to replace 0 with NA.
df %>%
mutate(g = 2 * (a == 2 ...
In the shell, what does “ 2>&1 ” mean?
...ay look like a good way to redirect stderr to stdout. However, it will actually be interpreted as "redirect stderr to a file named 1". & indicates that what follows is a file descriptor and not a filename. So the construct becomes: 2>&1.
...
Choice between vector::resize() and vector::reserve()
I am pre-allocating some memory to my a vector member variable. Below code is minimal part
4 Answers
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RRSet of type CNAME with DNS name foo.com. is not permitted at apex in zone bar.com
...
As per RFC1912 section 2.4:
A CNAME record is not allowed to coexist with any other data. In
other words, if suzy.podunk.xx is an alias for sue.podunk.xx, you
can't also have an MX record for suzy.podunk.edu, or an A record, or
even a TXT record. Especially do not try t...