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  1. C++ Standard Library
  2. STDCXX-624

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

    Details

    • 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
    • Labels:
      None
    • Environment:

      gcc 4.1.0 on SUSE Linux Enterprise Server 10 (x86_64)

    • Severity:
      Incorrect Behavior

      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
      

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            People

            • Assignee:
              sebor Martin Sebor
              Reporter:
              sebor Martin Sebor

              Dates

              • Created:
                Updated:
                Resolved:

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