[Boost-bugs] [Boost C++ Libraries] #13613: gcd performs modulo by zero which is undefined

Subject: [Boost-bugs] [Boost C++ Libraries] #13613: gcd performs modulo by zero which is undefined
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2018-06-20 12:45:53

#13613: gcd performs modulo by zero which is undefined
--------------------------------+---------------------------
 Reporter:  James E. King, III  |      Owner:  Daryle Walker
     Type:  Bugs                |     Status:  new
Milestone:  To Be Determined    |  Component:  integer
  Version:  Boost 1.67.0        |   Severity:  Problem
 Keywords:  ub                  |
--------------------------------+---------------------------
 Boost.Rational uses Boost.Integer's gcd method.  I Added Coverity Scan
 support to the Boost.Rational build and it identified an issue that needs
 investigation:

 CID 293013 (#4-12 of 12): Division or modulo by zero (DIVIDE_BY_ZERO)
 divide_by_zero: In function call gcd, modulo by expression 0 has undefined
 behavior. [hide details]

 (rational_test.cpp)
 470    BOOST_CHECK_EQUAL( boost::gcd<T>(  0,  -9), static_cast<T>( 9) );

 (rational.hpp)
 IntType gcd(IntType n, IntType m)
 {
     // Defer to the version in Boost.Integer

 >   1. divide_arg: n is used as a divisor in function gcd.
     return integer::gcd( n, m );
 }

-- 
Ticket URL: <https://svn.boost.org/trac10/ticket/13613>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.