[gcc/Linux] std::numeric_limits<int>traps = false when integer arithmetic traps
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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
Environment: gcc 4.1.0 on SUSE Linux Enterprise Server 10 (x86_64)
Reporter: Martin Sebor
Assignee: Mark Brown
Priority: Trivial
Fix For: 4.2.1
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
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