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Subject: Re: [boost] [units] gcc warnings
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-06-15 06:55:37

Jürgen Hunold wrote:
> I start using Boost.Units for a new project and found some
> annyoing warnings when compiling with "-Wall -Wextra" and
> "-Wconversion"

Don't do that and you won't get those warnings! (Just kidding.)

> /home/hunold/src/devel/boost/boost/units/io.hpp: In function 'int
> boost::units::get_flags(std::ios_base&, int)':
> /home/hunold/src/devel/boost/boost/units/io.hpp:163: warning:
> conversion to
> 'int' from 'long int' may alter its value [-Wconversion]
> Patch using an explicit static_cast<int> for the return value
> attached.

Do you know that the long int value can never exceed the range of int? If not, the static_cast will simply mask the problem. It would be better to check against std::numeric_limits<int>::max() before casting, and resort to an exception if the range is exceeded.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer, Core Software using std::disclaimer;
Susquehanna International Group, LLP

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