UINT_MAX the same as ULONG_MAX in C

Question

While solving exercises from the K&R C book, I stumbled upon the exercise 2.1.

At first I got as UINT_MAX as -1, but then I used the %u placeholder, but now its giving me the same number as ULONG_MAX.

In the book in Appendix B, they say that UINT_MAX should be 65535 and ULONG_MAX should be 4294967295, but when running the exercise, its giving me for both UINT_MAX and ULONG_MAX as 4294967295.

Why is that?

On Mac OS X 64-bit apps, `ULONG_MAX` = `ULONGLONG_MAX`, and `ULONG_MAX` ≠ `UINT_MAX`. Specifically `UINT_MAX=4294967295`, `ULONG_MAX=18446744073709551615`, and `ULONG_LONG_MAX=18446744073709551615` — bobobobo, Apr 15 '13 at 02:46

score 5 · Accepted Answer · answered Mar 17 '12 at 12:21

5

First of all, the right way to print an unsigned long is not %u but %lu. Second, the standard says the minimum value of UINT_MAX is 65535. It can be (and usually is) larger.

5.2.4.2.1 Sizes of integer types

Their implementation-deﬁned values shall be equal or greater in magnitude (absolute value) to those shown, with the same sign.

answered Mar 17 '12 at 12:21

cnicutar

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Ohh, I see I didnt see the minimum magnitude Thanks :D – hakuna matata Mar 17 '12 at 12:23

score 1 · Answer 2 · answered Mar 17 '12 at 12:25

1

On 32-bit platforms, int and long are usually the same, and so their max are also the same. The same for their unsigned counterparts of course.

answered Mar 17 '12 at 12:25

Some programmer dude

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score 0 · Answer 3 · answered May 27 '13 at 13:42

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The appendix is wrong. The only guarantee is that sizeof(long) >= sizeof(int) >= sizeof(char) note the possibility of equality.

answered May 27 '13 at 13:42

Ron Fox

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UINT_MAX the same as ULONG_MAX in C

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