How do you know isNaN() doesn't use this fact? In Java, the body of isNaN(n) is ... | Hacker News

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natep on Feb 13, 2010 | parent | context | favorite | on: WTFJS?

How do you know isNaN() doesn't use this fact? In Java, the body of isNaN(n) is simply 'return n!=n;'

cdavid on Feb 13, 2010 [–]

It depends on the implementation. In C, it is quite easy to have n != n optimized away when compilers have their compiler flags set on. That's why you should use isnan to test nan instead of any other techniques when using C or C++.

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