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Posted to dev@stdcxx.apache.org by "Martin Sebor (JIRA)" <ji...@apache.org> on 2007/10/30 00:35:51 UTC
[jira] Created: (STDCXX-624) [gcc/Linux]
std::numeric_limitstraps = false when integer arithmetic traps
[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
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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[jira] Updated: (STDCXX-624) [gcc/Linux]
std::numeric_limitstraps = false when integer arithmetic traps
Posted by "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 updated STDCXX-624:
--------------------------------
Assignee: Martin Sebor (was: Mark Brown)
Reassigning to self after accidentally assigning it to Mark.
> [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
> 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
>
>
> 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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