为什么在32位iOS上未将NSInteger定义为很长？

Question

NSInteger is defined this way:

#if __LP64__ || (TARGET_OS_EMBEDDED && !TARGET_OS_IPHONE) || TARGET_OS_WIN32 || NS_BUILD_32_LIKE_64
typedef long NSInteger;
#else
typedef int NSInteger;
#endif

This results in NSInteger being defined as int on 32-bit iOS even though int and long are the same anyway (both 4 bytes). Format strings like the following generate a warning with this definition:

NSInteger x = 4;
[NSString stringWithFormat: @"%ld", x];

// Warning: Values of type 'NSInteger' should not be used as format arguments;
// add an explicit cast to 'long' instead.

So does somebody know why NSInteger isn't always defined as long?

Answer 1

Historical reasons, where previous releases of APIs used int -- then were migrated to use typedef NSInteger ca. the 64-bit transition of OS X.

I suppose they could have changed for iOS, but that would have impacted a lot of existing and to-be-developed code if they were different on OS X and iOS.