如何处理 Xcode 警告“没有以前的函数原型......”？
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How to handle the Xcode warning "no previous prototype for function..."?
提问by Christian Schlensker
This warning is popping up a bunch in some third party libraries.
这个警告在一些第三方库中突然出现。
Is there a way to handle it without modifying the code (e.g. ignore the warning)?
有没有办法在不修改代码的情况下处理它（例如忽略警告）？
If I have to modify the code to fix it how do I do it?
如果我必须修改代码来修复它，我该怎么做？
Here's one of the code blocks that's causing a warning:
这是导致警告的代码块之一：
BOOL FBIsDeviceIPad() {
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES;
}
#endif
return NO;
}
回答by appmattus
Usually with warnings like this you can just define a function prototype at the top of your file, for instance:
通常对于这样的警告，您只需在文件顶部定义一个函数原型，例如：
BOOL FBIsDeviceIPad();
Butin C a method with nothing between the braces, i.e. ()actually implies there are an arbitrary number of parameters. Instead the definition should become (void)to denote noparameters:
但是在 C 中，大括号之间没有任何内容的方法，即()实际上意味着有任意数量的参数。相反，定义应该变成(void)表示没有参数：
BOOL FBIsDeviceIPad(void);
...
BOOL FBIsDeviceIPad(void) {
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 30200
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return YES;
}
#endif
return NO;
}
回答by bosmacs
In Xcode4, go to your project's Build Settings. Search for "prototype". There should be an option called "Missing Function Prototypes"; disable it. You can also do this to the specific target(s) in question.
在 Xcode4 中，转到项目的 Build Settings。搜索“原型”。应该有一个选项叫做“Missing Function Prototypes”；禁用它。您也可以对相关的特定目标执行此操作。
回答by thomsky
There are no warnings if such a function is defined as inline.
如果将此类函数定义为内联函数，则不会发出警告。
This may suffice as long as your function is optimized for inline use. http://msdn.microsoft.com/en-us/library/1w2887zk.aspx
只要您的函数针对内联使用进行了优化，这可能就足够了。 http://msdn.microsoft.com/en-us/library/1w2887zk.aspx
