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How expensive is RTTI?
...ique object for each type, even across dynamic linking boundaries. You can test &typeid(a) == &typeid(b), or just rely on the fact that the portable test typeid(a) == typeid(b) does actually just compare a pointer internally.
In GCC's preferred ABI, a class vtable always holds a pointer to ...
Why 0 is true but false is 1 in the shell?
...convention saying 0 means success, and other values mean some error.
With test, [ ] or [[ ]] operators, bash conditions evaluate as true in case of an exit code of 0 (the result of /bin/true). Otherwise they evaluate as false.
Strings are evaluated differently than exit codes:
if [ 0 ] ; then ech...
How to add percent sign to NSString
...helps in some cases, it is possible to use the unicode character:
NSLog(@"Test percentage \uFF05");
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C语言结构体里的成员数组和指针 - C/C++ - 清泛网 - 专注C/C++及内核技术
...简单化一下代码：
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struct test{
int i;
char *p;
};
上面代码中，test结构中i和p指针，在C的编译器中保存的是相对地址——也就是说，他们的地址是相对于struct test的实例的。如果...
How to have an automatic timestamp in SQLite?
...CURRENT_TIMESTAMP NOT NULL
);
INSERT INTO my_table(name, sqltime) VALUES('test1', '2010-05-28T15:36:56.200');
INSERT INTO my_table(name, sqltime) VALUES('test2', '2010-08-28T13:40:02.200');
INSERT INTO my_table(name) VALUES('test3');
This is the result:
SELECT * FROM my_table;
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Is there a use-case for singletons with database access in PHP?
... allow for multiple databases--no other code changes.
The second issue is testing (And honestly, this is the same as the first issue). Sometimes you want to replace your database with a mock database. In effect this is a second instance of the database object. This is much harder to do with stat...
Test if something is not undefined in JavaScript
...for me:
typeof possiblyUndefinedVariable !== "undefined"
I will have to test that in other browsers and see how things go I suppose.
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When to use enumerateObjectsUsingBlock vs. for
...ion allows the collection class to enumerate contents as quickly as the fastest traversal of the native storage format. Likely irrelevant for arrays, but it can be a huge difference for dictionaries.
"Don't use enumerateObjectsUsingBlock when you need to modify local variables" - not true; you can ...
Checking if object is empty, works with ng-show but not from controller?
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thanks! actually i ended up testing it with undefined and it worked great. thanks.
– Martin
Jul 27 '13 at 13:09
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Access denied for user 'test'@'localhost' (using password: YES) except root user
...Then when you go to try to sign in to MySQL, type it in like this:
Hit 'Test Connection' and enter your password 'password'.
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