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Concurrent vs serial queues in GCD
I'm struggling to fully understand the concurrent and serial queues in GCD. I have some issues and hoping someone can answer me clearly and at the point.
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php is null or empty?
...===.
When use ==, as you did, PHP treats NULL, false, 0, the empty string, and empty arrays as equal.
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Are PDO prepared statements sufficient to prevent SQL injection?
...erver's expecting on the connection both to encode ' as in ASCII i.e. 0x27 and to have some character whose final byte is an ASCII \ i.e. 0x5c. As it turns out, there are 5 such encodings supported in MySQL 5.6 by default: big5, cp932, gb2312, gbk and sjis. We'll select gbk here.
Now, it's very i...
User recognition without cookies or local storage
I'm building an analytic tool and I can currently get the user's IP address, browser and operating system from their user agent.
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Why is the gets function so dangerous that it should not be used?
...hat.)
It remained an official part of the language up to the 1999 ISO C standard, but
it was officially removed by the 2011 standard. Most C implementations still support it, but at least gcc issues a warning for any code that uses it.
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Is there a replacement for unistd.h for Windows (Visual C)?
...n't exist. Removing it, I get complaints about misssing prototypes for 'srandom', 'random', and 'getopt'.
I know I can replace the random functions, and I'm pretty sure I can find/hack-up a getopt implementation.
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Why does auto a=1; compile in C?
... old C keyword that means "local scope". auto a is the same as auto int a, and because local scope is the default for a variable declared inside a function, it's also the same as int a in this example.
This keyword is actually a leftover from C's predecessor B, where there were no base types: every...
What is the difference between LR, SLR, and LALR parsers?
What is the actual difference between LR, SLR, and LALR parsers? I know that SLR and LALR are types of LR parsers, but what is the actual difference as far as their parsing tables are concerned?
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What is the difference between ELF files and bin files?
The final images produced by compliers contain both bin file and extended loader format ELf file ,what is the difference between the two , especially the utility of ELF file.
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How do you get the logical xor of two variables in Python?
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Although this is clever and short, I'm not convinced it's clean. When someone reads this construct in the code, is it immediately obvious to them that this is an xor operation? I felt obliged to add a comment - a sign for me that I'm writing unclear...