[jira] Closed: (STDCXX-624) [gcc/Linux] std::numeric_limits::traps = false when integer arithmetic traps

["Martin Sebor (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/STDCXX-624?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Martin Sebor closed STDCXX-624.
-------------------------------

    Resolution: Fixed

Fixed in [r589912|http://svn.apache.org/viewcvs?view=rev&rev=589912].
Regression test committed in [r641091|http://svn.apache.org/viewcvs?view=rev&rev=641091].
Merged to 4.2.x in [r589913|http://svn.apache.org/viewcvs?view=rev&rev=589913] and [r642845|http://svn.apache.org/viewcvs?view=rev&rev=642845].

> [gcc/Linux] std::numeric_limits<int>::traps = false when integer arithmetic traps
> ---------------------------------------------------------------------------------
>
>                 Key: STDCXX-624
>                 URL: https://issues.apache.org/jira/browse/STDCXX-624
>             Project: C++ Standard Library
>          Issue Type: Bug
>          Components: 18. Language Support
>    Affects Versions: 4.2.0
>         Environment: gcc 4.1.0 on SUSE Linux Enterprise Server 10 (x86_64)
>            Reporter: Martin Sebor
>            Assignee: Martin Sebor
>            Priority: Trivial
>             Fix For: 4.2.1
>
>   Original Estimate: 4h
>          Time Spent: 2h
>  Remaining Estimate: 2h
>
> As an extension, stdcxx defines the value of {{std::numeric_limits<T>::traps}} for integer {{T}} to be true when there exists an arithmetic operation on type T that traps for some value of {{T}}. Based on this definition the program below should always run successfully to completion but when compiled with gcc 4.1.0 with optimization enabled on SUSE Linux Enterprise Server 10 (x86_64) it aborts at runtime. (This is also why the example program [limits.cpp|http://svn.apache.org/repos/asf/stdcxx/trunk/examples/manual/limits.cpp] produces a {{DIFF}} result in some builds).
> {code}
> $ cat t.cpp && make t && ./t
> #include <cassert>
> #include <cstdio>
> #include <cstdlib>
> #include <limits>
> char digits[] = " +0.?23456789e+01";
> int main ()
> {
>     digits [4] = '0';
>     const int zero = (int)std::strtod (digits, 0);
>     digits [4] = '1';
>     const int x = (int)std::strtod (digits, 0);
>     if (!std::numeric_limits<int>::traps) {
>         const int div = x / zero;
>         const int mod = x % zero;
>         std::printf ("%d, %d\n", div, mod);
>     }
> }
> gcc -c -I/amd/devco/sebor/stdcxx-4.2.x/include/ansi   -pthread -I/amd/devco/sebor/stdcxx-4.2.x/include -I/build/sebor/stdcxx-4.2.x-gcc-4.1.0-12D/include -I/amd/devco/sebor/stdcxx-4.2.x/examples/include  -pedantic -nostdinc++ -O2   -W -Wall -Wcast-qual -Winline -Wshadow -Wwrite-strings -Wno-long-long -Wcast-align   t.cpp
> gcc t.o -o t -pthread  -L/build/sebor/stdcxx-4.2.x-gcc-4.1.0-12D/lib  -Wl,-R/build/sebor/stdcxx-4.2.x-gcc-4.1.0-12D/lib -lstd12D -lsupc++ -lm 
> Floating point exception
> {code}

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