| // checking if floating point math traps |

| |

| /*************************************************************************** |

| * |

| * Licensed to the Apache Software Foundation (ASF) under one or more |

| * contributor license agreements. See the NOTICE file distributed |

| * with this work for additional information regarding copyright |

| * ownership. The ASF licenses this file to you under the Apache |

| * License, Version 2.0 (the License); you may not use this file |

| * except in compliance with the License. You may obtain a copy of |

| * the License at |

| * |

| * http://www.apache.org/licenses/LICENSE-2.0 |

| * |

| * Unless required by applicable law or agreed to in writing, software |

| * distributed under the License is distributed on an "AS IS" BASIS, |

| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or |

| * implied. See the License for the specific language governing |

| * permissions and limitations under the License. |

| * |

| * Copyright 1999-2007 Rogue Wave Software, Inc. |

| * |

| **************************************************************************/ |

| |

| /* IEEE 754 (IEC 559 supeseded by IEC 60559) specifies that |

| * the following operations return NaN unless they trap: |

| * |

| * 1. sqrt (n); n < 0 |

| * 2. rem (x, 0.0), rem (inf, x) |

| * 3. 0 * inf |

| * 4. 0.0 / 0.0, inf / inf |

| * 5. inf - inf (when both inf have the same sign) |

| * |

| * Traps are defined as kind of an exception, typically |

| * causing the delivery of SIGFPE (e.g., with Compaq C++ |

| * on Tru64 UNIX, except when using the -ieee flag which |

| * disables traps as required by C). |

| */ |

| |

| #include "nodbg.h" |

| |

| double dbl_get_zero (); |

| double dbl_get_one (); |

| |

| int main (int argc, char*[]) |

| { |

| nodbg (); |

| |

| double dbl_inf; |

| double dbl_nan; |

| |

| double dbl_zero = dbl_get_zero (); |

| double dbl_one = dbl_get_one (); |

| |

| // compute infinity (division by zero may trap) |

| dbl_inf = dbl_one / dbl_zero; |

| |

| // computation involving infinities that might trap |

| dbl_nan = dbl_zero * dbl_inf; // #3 |

| dbl_nan = dbl_zero / dbl_zero; // #4a |

| dbl_nan = dbl_inf / dbl_inf; // #4b |

| dbl_nan = dbl_inf - dbl_inf; // #5 |

| |

| if (argc > 2) |

| return dbl_nan; |

| |

| if (argc > 1) |

| return dbl_inf; |

| |

| // NEGATIVE test: successful exit status indicates a failure |

| return 0; |

| } |

| |

| // foil optimizers |

| double dbl_get_zero () |

| { |

| static double value = 0.0; |

| |

| return value; |

| } |

| |

| |

| double dbl_get_one () |

| { |

| static double value = 1.0; |

| |

| return value; |

| } |