[STDCXX-624] [gcc/Linux] std::numeric_limits<int>::traps = false when integer arithmetic traps

• Type: Bug
• Status: Closed
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 4.2.0
• Fix Version/s: 4.2.1
• Component/s: 18. Language Support

Environment

gcc 4.1.0 on SUSE Linux Enterprise Server 10 (x86_64)

• Severity: Incorrect Behavior
• Assignee: Martin Sebor
• Reporter: Martin Sebor
• Created: 29/Oct/07 23:35
• Updated: 30/Mar/08 23:52
• Resolved: 30/Mar/08 23:52

Description

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 produces a DIFF result in some builds).

$ 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