# \[ruby-trunk - Bug #10464\] \[Closed\] Bignum同士の乗算の不具合

**URL:** <https://www.ruby-forum.com/t/ruby-trunk-bug-10464-closed-bignum/232871>\
**Category:** Development\
**Created:** [November 1, 2014, 9:14am UTC](https://www.ruby-forum.com/t/ruby-trunk-bug-10464-closed-bignum/232871 "2014-11-01T09:14:13Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [November 1, 2014, 9:14am UTC](https://www.ruby-forum.com/t/ruby-trunk-bug-10464-closed-bignum/232871/1 "2014-11-01T09:14:13Z")

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Issue #10464 has been updated by Akira T…

Status changed from Open to Closed  
% Done changed from 0 to 100

Applied in changeset r48222.

* * *

- bignum.c (bary\_mul\_balance\_with\_mulfunc): Fix free work area  
location.  
[ruby-dev:48723] [Bug #10464]  
[ruby-core:66044] [Bug #10465]  
Reported by Kohji Nishihama.

* * *

Bug #10464: Bignum同士の乗算の不具合

> **[Bug #10464: Bignum同士の乗算の不具合 - Ruby master - Ruby Issue Tracking System](https://bugs.ruby-lang.org/issues/10464#change-49765)**
>
> Redmine

- Author: Kohji Nishihama
- Status: Closed
- Priority: Normal
- Assignee: Kohji Nishihama
- Category:
- Target version: next minor
- ruby -v: ruby 2.1.4p265 (2014-10-27 revision 48166) [i386-mingw32]
- Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN

* * *

あるBignum同士を乗算すると、誤った値が出力されます。  
OSはWindows Vista Home Premium。  
なお、ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-mswin32]、ruby 1.9.3p484  
(2013-11-22) [i386-mingw32]、200: ruby 2.0.0p353 (2013-11-22)  
[i386-mingw32]では正常に動作し、  
ruby 2.1.3p242 (2014-09-19 revision 47630) [i386-mingw32]では同様に不具合が生じました。

$ ruby bug.rb  
5470148495 # 誤った乗算の値  
1943359375 # 真の乗算の値  
#なお、冗長になるので下10桁のみを表示しています

—Files--------------------------------  
bug.rb (16.9 KB)