There are two ways to determine this: at runtime (i.e. in your running code), and at compile time (i.e. before the code is compiled). Let’s take a look at both options.
Runtime Check
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// testing for 64bit at runtime if (sizeof(void*) == 4) { self.textLabel.text = @"You're running in 32 bit"; } else if (sizeof(void*) == 8) { self.textLabel.text = @"You're running in 64 bit"; } |
Determines the size of a pointer.
Compile Time Check
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#if __LP64__ // you're running 64bit #else // you're running 32bit #endif |
Asks the compiler which architecture it compiles for.