From: Jacob Fugal Date: 2006-07-28T02:53:58+09:00 Subject: Re: [ ruby-Bugs-4970 ] bug in printf On 7/26/06, Yukihiro Matsumoto wrote: > In message "Re: [ ruby-Bugs-4970 ] bug in printf" > on Thu, 27 Jul 2006 01:11:28 +0900, "Jacob Fugal" writes: > > |Ok, that makes sense. Should we maybe patch the documentation on > |Kernel#sprintf to mention those? > > Perhaps. Would anyone volunteer to make a patch? How's this look? It's probably too verbose, and I'm not even sure about the accuracy, but it could be a starting point for someone else to clean up... Index: sprintf.c =================================================================== RCS file: /src/ruby/sprintf.c,v retrieving revision 1.65 diff -u -r1.65 sprintf.c --- sprintf.c 26 Jul 2006 08:28:57 -0000 1.65 +++ sprintf.c 27 Jul 2006 17:51:17 -0000 @@ -216,7 +216,12 @@ * s | Argument is a string to be substituted. If the format * | sequence contains a precision, at most that many characters * | will be copied. - * u | Treat argument as an unsigned decimal number. + * u | Treat argument as an unsigned decimal number. Negative integers + * | are displayed as a 32 bit two's complement plus one for the + * | underlying architecture; that is, 2 ** 32 + n. However, since + * | Ruby has no inherent limit on bits used to represent the + * | integer, this value is preceded by two dots (..) in order to + * | indicate a infinite number of leading sign bits. * X | Convert argument as a hexadecimal number using uppercase * | letters. Negative numbers will be displayed with two * | leading periods (representing an infinite string of @@ -233,6 +238,7 @@ * sprintf("%1$*2$s %2$d %1$s", "hello", 8) #=> " hello 8 hello" * sprintf("%1$*2$s %2$d", "hello", -8) #=> "hello -8" * sprintf("%+g:% g:%-g", 1.23, 1.23, 1.23) #=> "+1.23: 1.23:1.23" + * sprintf("%u", -123) #=> "..4294967173" */ VALUE