遇到& quot;清理:& quot;在Xcode中的Foundation代码示例中.这是什么? [英] encountered "cleanup:" in a Foundation code sample in Xcode. What is this?

问题描述

因此在即将发布的 Core Audio Book 我遇到了一个陌生的符号

so in some sample code from this upcoming Core Audio Book i've encountered an unfamiliar symbol

cleanup:

在调用某些dispose(myStuff)函数之前使用.它前面没有'@'或'#'.似乎您可以输入任何单词，后跟冒号，它会像注释一样起作用吗?

which is used before some dispose(myStuff) functions are called. It's not preceded by an '@' or a '#'. Seems you can type any word, followed by a colon, and it will act like a comment?

int main (int argc, const char * argv[])
{
    @autoreleasepool 
    {
        NSLog(@"i am code.");

    cleanup:    
    foop:
    lol:

        NSLog(@"even more code.");
    }
    return 0;
}

推荐答案

这不是评论.这是一个标签，用于指定 goto 的位置.

It's not a comment. It's a label specifying a location for goto.

例如

int main (int argc, const char * argv[])
{
    while (1) {
        printf("Is this an infinite loop?\n");
        goto endLabel;
    }

    endLabel:    

    printf("No.");

    return 0;
}

输出:

Is this an infinite loop?
No.

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