xcode 自动修复“字符串文字的直接比较具有未定义的行为”
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原文地址: http://stackoverflow.com/questions/16246462/
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Fixing "direct comparison of a string literal has undefined behavior" automatically
提问by Someone
In Xcode, I'm getting the error "direct comparison of a string literal has undefined behavior," and I know why I'm getting it, but is there some way for me to click a button and have Xcode remove it? I'm saying this because in 370 places in my app I've gotten it.
在 Xcode 中，我收到错误“字符串文字的直接比较具有未定义的行为”，我知道我为什么会得到它，但是有什么方法可以让我单击按钮并让 Xcode 将其删除？我这么说是因为在我的应用程序的 370 个地方我已经得到了它。
回答by rickster
The clang option to disable this warning is -Wno-objc-literal-compare.
禁用此警告的 clang 选项是-Wno-objc-literal-compare.
However, warnings are there for a reason; this one is because comparing against NSString literals using ==is not guaranteed to behave as you might expect. Use isEqual:or isEqualToString:instead and you can both get rid of this warning and avoid having this turn into a bug for you later.
然而，警告是有原因的；这是因为与使用 NSString 文字进行比较==并不能保证其行为符合您的预期。使用isEqual:或isEqualToString:代替，您既可以摆脱此警告，又可以避免以后将其变成错误。
回答by Sourabh Kumbhar
You can avoid the warning using `isEqualToString` instead of `==`.
`==`?simply compares the pointers, which will usually be different even
if their contents are the same. The`isEqualToString`?method compares
their contents.
