英文:
Pipe character in Golang
问题
管道符号 | 在这里表示按位或（bitwise OR）操作。在这个例子中，svc.AcceptStop、svc.AcceptShutdown 和 svc.AcceptPauseAndContinue 是一些常量，它们的值是按位或操作的结果。按位或操作将两个二进制数的对应位进行逻辑或运算，如果任意一个位为1，则结果的对应位也为1。
英文:
In the package golang.org/x/sys/windows/svc there is an example that contains this code:
const cmdsAccepted = svc.AcceptStop | svc.AcceptShutdown | svc.AcceptPauseAndContinue
What does the pipe | character mean?
答案1
得分: 41
如其他人所说，这是位运算中的[包含]或运算符。更具体地说，这些运算符被用于创建位掩码标志，这是一种基于位运算组合选项常量的方式。例如，如果你有一些选项常量是二的幂次方，像这样：
const (
red = 1 << iota // 1 (二进制: 001) (2的0次方)
green // 2 (二进制: 010) (2的1次方)
blue // 4 (二进制: 100) (2的2次方)
)
然后你可以使用位或运算符将它们组合起来，像这样：
const (
yellow = red | green // 3 (二进制: 011) (1 + 2)
purple = red | blue // 5 (二进制: 101) (1 + 4)
white = red | green | blue // 7 (二进制: 111) (1 + 2 + 4)
)
因此，它简单地提供了一种基于位运算组合选项常量的方式，依赖于二进制数制中表示二的幂次方的方式；注意在使用或运算符时二进制位是如何组合的。（有关更多信息，请参见C编程语言中的此示例。）因此，通过组合你的示例中的选项，你只是允许服务接受停止、关闭和暂停和继续命令。
英文:
As others have said, it's the bitwise [inclusive] OR operator. More specifically, the operators are being used to create bit mask flags, which is a way of combining option constants based on bitwise arithmetic. For example, if you have option constants that are powers of two, like so:
const (
red = 1 << iota // 1 (binary: 001) (2 to the power of 0)
green // 2 (binary: 010) (2 to the power of 1)
blue // 4 (binary: 100) (2 to the power of 2)
)
Then you can combine them with the bitwise OR operator like so:
const (
yellow = red | green // 3 (binary: 011) (1 + 2)
purple = red | blue // 5 (binary: 101) (1 + 4)
white = red | green | blue // 7 (binary: 111) (1 + 2 + 4)
)
So it simply provides a way for you to combine option constants based on bitwise arithmetic, relying on the way that powers of two are represented in the binary number system; notice how the binary bits are combined when using the OR operator. (For more information, see this example in the C programming language.) So by combining the options in your example, you are simply allowing the service to accept stop, shutdown and pause and continue commands.
答案2
得分: 4
Go编程语言的规范可以在《Go编程语言规范》中找到。
英文:
> The Go Programming Language Specification
>
> Arithmetic operators
>
> | bitwise OR integers
The Go programming language is defined in The Go Programming Language Specification.
答案3
得分: 1
| 在这里不是管道字符，而是或字符，是位操作中的一种。
例如，1 | 1 = 1，1 | 2 = 3，0 | 0 = 0。
英文:
The | is not pipe character here,but or character,one of bit manipuations.
For example,1 | 1 = 1,1 | 2 = 3,0 | 0 = 0.
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