-[NSDate timeIntervalSinceDate:] returns very small number on GCC 4.2, but works as expected on LLVM-GCC 4.2 on iOS4.3 Simulator

Question

On iOS 4.3 Simulator, the following code returns a very small number: 1e-700 on GCC 4.2, but works as expected on LLVM-GCC 4.2. Any ideas?

NSDate *selectedDate = self.datepicker.date; // guaranteed to be before now
NSTimeInterval interval = [nowDate timeIntervalSinceDate:selectedDate];

these values change with each run, but here is an example set of output

selectedDate: 1981-06-02 16:27:34 +0000

nowDate: 2011-08-03 05:18:36 +0000

interval: 5.489011535689859e-277

running [nowDate timeIntervalSinceDate:selectedDate] in GDB: 952001462.97236204 (this is my expected value)

How are you determining that `interval` contains 1e-700 on GCC 4.2? — Lily Ballard, Aug 02 '11 at 21:17
I print it in GDB with the following command: p (NSTimeInterval) interval — Heath Borders, Aug 02 '11 at 21:40
Can you show the values of selectedDate and nowDate when you're doing this test? — Joshua Weinberg, Aug 02 '11 at 22:08
@HeathBorders It sounds like your question resolved itself. Please mark it as closed. — Jeremy W. Sherman, Sep 06 '12 at 20:25

score 0 · Accepted Answer · answered Apr 28 '12 at 11:50

0

This might be a bug with GCC. I think you should fill a bug report and see what Apple has to say.

answered Apr 28 '12 at 11:50

David Murray

I retested with iOS 5.1, and can't replicate the issue. – Heath Borders May 22 '12 at 15:30

score -1 · Answer 2 · answered Oct 04 '11 at 12:50

-1

The unexpected value is an overflow.

answered Oct 04 '11 at 12:50

Ameer Sheikh

2 Answers2