大约有 18,000 项符合查询结果（耗时：0.0272秒） [XML]
How efficient is locking an unlocked mutex? What is the cost of a mutex?
...
123
I have the choice in between either having a bunch of mutexes or a single one for an object...
Is gcc's __attribute__((packed)) / #pragma pack unsafe?
...cked__)) my_struct {
char c;
int i;
};
struct my_struct a = {'a', 123};
struct my_struct *b = &a;
int c = a.i;
int d = b->i;
int *e __attribute__((aligned(1))) = &a.i;
int *f = &a.i;
Here, the type of a is a packed struct (as defined above). Similarly, b is a pointer to a p...
Why is “while ( !feof (file) )” always wrong?
...tespace. Using C++ iostreams, it goes like this:
std::string input = " 123 "; // example
std::istringstream iss(input);
int value;
if (iss >> value >> std::ws && iss.get() == EOF) {
consume(value);
} else {
// error, "input" is not parsable as an inte...
Parameterize an SQL IN clause
...
123
That will be hella slow
– Matt Rogish
Dec 3 '08 at 16:43
...
Seeking clarification on apparent contradictions regarding weakly typed languages
...f these things at the same time. So you can, for example, write:
$foo = "123" + "456"; # $foo = 579
$bar = substr($foo, 2, 1); # $bar = 9
$bar .= " lives"; # $bar = "9 lives"
$foo -= $bar; # $foo = 579 - 9 = 570
Of course, as you correctly note, all...
Colors in JavaScript console
...36px 121px hsl(653.4, 100%, 50%), -38px 122px hsl(658.8, 100%, 50%), -39px 123px hsl(664.2, 100%, 50%), -41px 124px hsl(669.6, 100%, 50%), -42px 125px hsl(675, 100%, 50%), -43px 126px hsl(680.4, 100%, 50%), -45px 127px hsl(685.8, 100%, 50%), -46px 128px hsl(691.2, 100%, 50%), -47px 129px hsl(696.6, ...
PHP parse/syntax errors; and how to solve them
... trying to dereference constants (before PHP 5.6) as arrays:
$var = const[123];
⇑
At least PHP interprets that const as a constant name.
If you meant to access an array variable (which is the typical cause here), then add the leading $ sigil - so it becomes a $varname.
You are trying to...
Programmatically Lighten or Darken a hex color (or rgb, and blend colors)
... and accepts standard RGB colors in the form of strings. For example: "rgb(123,45,76)" or "rgba(45,15,74,0.45)".
Shades colors to white or black by percentage.
Blends colors together by percentage.
Does Hex2RGB and RGB2Hex conversion at the same time, or solo.
Accepts 3 digit (or 4 digit w/ alpha) H...
What does the `forall` keyword in Haskell/GHC do?
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123
Can anybody completely explain the forall keyword in clear, plain English?
No. (Well, may...
In Java, what is the best way to determine the size of an object?
...
123
You should use jol, a tool developed as part of the OpenJDK project.
JOL (Java Object Layo...