如何让Xcode 3.1编译器在if语句中警告赋值运算符？ [英] How to have the Xcode 3.1 compiler warn of assignment operator in an if statement?
问题描述
我尝试尽可能地搜索文档和互联网，但是如果在if语句中使用赋值运算符，我无法让Xcode编译器发出警告。 p>
我来自RealBasic，在那里我有一个非常强的习惯键入这种比较：
如果x = 5则...
当然，语法分配x的值5然后测试结果以查看它是否为非零，并且正确运算符是：
if（x == 5）{...}
编译器应该能够警告如果有一个赋值在一个if比较，但我不能找到如何打开它在Xcode 3.1 / gcc。我发现 -pedantic 选项，但是似乎没有产生警告。
花费了大量的时间两次，现在跟踪bug，结果是=而不是==，我想要一个警告的帮助。
我知道我可以这样做（这将导致编译器错误）：
if（5 = x）{。 ..}
...但这需要改变根深蒂固的编码习惯。
谢谢！
p>在ennuikiller的回答中的链接导致了我需要的。
这里有一些更多的信息，可能会在将来找到这个：
-
编译器警告是缺少括号和括号或-Wparentheses。
- p>通过在Xcode中为当前
目标选择获取信息来打开警告。 -
正如我终于发现的，iPhone模拟器SDK
-
将SDK切换到iPhone设备会显示GCC 4.2警告
部分，其中包括缺少
大括号和括号。 -
在iPhone设备SDK中打开该选项后， $ b给Similator显示
User-Defined构建设置已添加
：
GCC_WARN_MISSING_PARENTHESES=
/> -
如果在if语句中确实需要赋值，可以
加上括号以避免警告。
（双括号示例）
if（（x = 5））{...}
像一个魅力，虽然它不喜欢苹果的标准：
if（self = [super init]）{...}
我可能会保留原样，虽然如果我结束了大量的一个项目，我将双括号或分割成一个单独的行。
谢谢！
I've tried searching the documentation and the internet as best as I'm able, but I haven't been able to get the Xcode compiler to issue a warning if the assignment operator is used in an if statement.
I'm coming from RealBasic, where I've got an extremely strong habit of typing this sort of comparison:
if x = 5 then ...
In C, of course, that syntax assigns x the value of 5 then tests the result to see if it's nonzero, and the "correct" operator is:
if (x == 5) { ... }
I've found several mentions that the compiler should be able to warn if there is an assignment made in an if comparison, but I cannot find how to turn it on in Xcode 3.1/gcc. I found the -pedantic option, but that didn't seem to generate the warning.
Since I've spent a fair amount of time twice now tracking down bugs that turned out to be "=" instead of "==", I'd like the help of a warning.
I know that I can do this instead (which will cause a compiler error):
if (5 = x) { ... }
...but that requires changing ingrained coding habits, too. Not to mention that it looks clumsy and backward.
Thanks!
The link in ennuikiller's answer did lead to what I needed.
Here's a bit more information for anyone who might find this in the future:
The compiler warning is "Missing braces and parentheses", or -Wparentheses.
The warning is turned on by choosing Get Info for the current target in Xcode.
As I finally found out, the iPhone Simulator SDK does not show this compiler option.
Switching the SDK to iPhone Device will show the GCC 4.2 Warnings section, which includes "Missing braces and parentheses".
After turning on that option in the iPhone Device SDK, switching back to the Similator shows that a "User-Defined" build setting has been added:
GCC_WARN_MISSING_PARENTHESES= "YES".If an assignment is really desired in an if statement, you can double the parentheses to avoid the warning.
(Double-parentheses example:)
if ((x = 5)) { ... }
The warning works like a charm, though it does dislike Apple's standard:
if (self = [super init]) { ... }
I'll probably leave those as-is, though if I end up with a huge amount of them in a project, I'll either double the parenthesis or break out the assignment into a separate line.
Thanks!
这篇关于如何让Xcode 3.1编译器在if语句中警告赋值运算符？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
