blocks|key|2812122|text|如果在OS+(64位)上编译，则会收到此警告，因为在该平台上，NSInteger被定义为long，是一个64位整数。另一方面，%25i格式是用于32位int的。因此，格式和实际参数的大小不匹配。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2812123|由于NSInteger是32位还是64位，取决于平台，编译器通常建议向long添加强制转换。|2812124|更新:由于iOS+7现在也支持64位，因此在为iOS编译时也会收到同样的警告。|2812125|entityMap^0|V|9|18|4|1R|2|21|3|0|2|9|Z|4|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]|$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|Z|8|@]|D|@]|E|$]]|$1|J|3|-4|5|6|7|10|8|@]|D|@]|E|$]]]|K|$]]

You get this warning if you compile on OS X (64-bit), because on that platform <code>NSInteger</code> is defined as <code>long</code> and is a 64-bit integer. The <code>%i</code> format, on the other hand, is for <code>int</code>, which is 32-bit. So the format and the actual parameter do not match in size.

Since <code>NSInteger</code> is 32-bit or 64-bit, depending on the platform, the compiler recommends
to add a cast to <code>long</code> generally.

Update: Since iOS 7 supports 64-bit now as well, you can get the same warning when compiling
for iOS.

blocks|key|190667|text|如果您的格式说明符与您的数据类型匹配，则不必强制转换为任何类型。请参阅Martin+R的答案，了解有关如何根据本机类型定义NSInteger的详细信息。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|190668|因此，对于打算为64位环境构建的代码，您可以像这样编写日志语句：|190669|NSLog(@"%25ld",++myInt);+|code-block|syntax|javascript|190670|而对于32位环境，您可以这样写：|190671|NSLog(@"%25d",++myInt);+|190672|并且它将在没有强制转换的情况下工作。|190673|使用强制转换的一个原因是，好的代码往往是跨平台移植的，如果你显式地转换你的变量，它将在32位和64位上干净地编译：|190674|NSLog(@"%25ld",++(long)myInt);|190675|请注意，这不仅适用于NSLog语句，毕竟它们只是调试辅助工具，而且还适用于[NSString+stringWithFormat:]和各种派生消息，它们是生产代码的合法元素。|190676|entityMap^0|1P|9|0|0|0|0|0|0|0|0|11|S|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|15|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|17|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|18|8|@]|D|@]|E|$]]|$1|U|3|V|5|J|7|19|8|@]|D|@]|E|$K|L]]|$1|W|3|X|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|Y|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|Z|$]]

You don't have to cast to anything if your format specifiers match your data types. See Martin R's answer for details on how <code>NSInteger</code> is defined in terms of native types.

So for code intended to be built for 64-bit environments, you can write your log statements like this:

<pre><code>NSLog(@"%ld", myInt); 
</code></pre>

while for 32-bit environments you can write:

<pre><code>NSLog(@"%d", myInt); 
</code></pre>

and it will all work without casts.

One reason to use casts anyway is that good code tends to be ported across platforms, and if you cast your variables explicitly it will compile cleanly on both 32 and 64 bit:

<pre><code>NSLog(@"%ld", (long)myInt);
</code></pre>

And notice this is true not just for NSLog statements, which are just debugging aids after all, but also for <code>[NSString stringWithFormat:]</code> and the various derived messages, which are legitimate elements of production code.

blocks|key|190702|text|不需要将NSInteger传递给NSLog，只需传递NSNumber即可。这将绕过所有类型转换并选择正确的字符串格式说明符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|190703|NSNumber+foo+=+@9000;
NSLog(@"foo:+%25@",+foo);
NSInteger+bar+=+9001;
NSLog(@"bar:+%25@",+@(bar));|code-block|syntax|javascript|190704|它也适用于NSUIntegers，而不必担心这一点。请参阅NSInteger+and+NSUInteger+in+a+mixed+64bit+/+32bit+environment的答案|offset|length|190705|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/20355439/nsinteger-and-nsuinteger-in-a-mixed-64bit-32bit-environment^0|0|0|T|1P|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

Instead of passing an NSInteger to NSLog, just pass an NSNumber. This will get around all the casts and choosing the right string format specifier.

<pre><code>NSNumber foo = @9000;
NSLog(@"foo: %@", foo);
NSInteger bar = 9001;
NSLog(@"bar: %@", @(bar));
</code></pre>

It also works for NSUIntegers without having to worry about that. 
See answer to <a href="https://stackoverflow.com/questions/20355439/nsinteger-and-nsuinteger-in-a-mixed-64bit-32bit-environment">NSInteger and NSUInteger in a mixed 64bit / 32bit environment</a>

blocks|key|2812272|text|OS+X使用多种数据类型-NSInteger、NSUInteger、CGFloat和CFIndex-来提供在32位和64位环境中表示值的一致方法。在32位环境中，NSInteger和NSUInteger分别定义为int和unsigned+int。在64位环境中，NSInteger和NSUInteger分别定义为long和unsigned+long。为了避免需要根据平台使用不同的printf样式的类型说明符，您可以在32位和64位环境中使用this+link中显示的说明符。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2812273|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html^0|65|9|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

OS X uses several data types—NSInteger, NSUInteger,CGFloat, and CFIndex—to provide a consistent means of representing values in 32- and 64-bit environments. In a 32-bit environment, NSInteger and NSUInteger are defined as int and unsigned int, respectively. In 64-bit environments, NSInteger and NSUInteger are defined as long and unsigned long, respectively. To avoid the need to use different printf-style type specifiers depending on the platform, you can use the specifiers shown in <a href="https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html" rel="nofollow">this link</a> for both 32 bit and 64 bit environment.

blocks|key|2812290|text|它在使用NSLog(@"%25ld",++(long)myInt);时保持警告，但在iOS+10中将更改声明为long+myInt+=+1804809223;后停止警告。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2812291|entityMap^0|4|S|1H|O|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

It keeps warning while using <code>NSLog(@"%ld", (long)myInt);</code>, but stops warning after change declaration to <code>long myInt = 1804809223;</code> in iOS 10.

<pre><code>NSInteger myInt = 1804809223;
NSLog(@"%i", myInt); &lt;==== 
</code></pre>

The code above produces an error:

<blockquote>
 Values of type 'NSInteger' should not be used as format arguments; add an explicit cast to 'long' instead
</blockquote>

The corrected <code>NSLog</code> message is actually <code>NSLog(@"%lg", (long) myInt);</code>. Why do I have to convert the integer value of <code>myInt</code> to <code>long</code> if I want the value to display?

Why does an NSInteger variable have to be cast to long when used as a format argument?

编译器

NSInteger myInt = 1804809223;NSLog(@"%i", myInt); <==== 上面的代码产生了一个错误：“NSInteger”“类型的长值不应用作格式参数；请改为将显式强制转换为”“”“更正后的NSLog消息实际上是NSLog(@"%lg", (long) myInt);。如果我想要显...

问当用作格式参数时，为什么NSInteger变量必须转换为long？
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问当用作格式参数时，为什么NSInteger变量必须转换为long？
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