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trapping floating point errors

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gregorylburgess edited this page Mar 4, 2016 · 1 revision

Trapping floating point errors

Dave's simple additions to a TPL file to trap floating point errors

Add #include <fenv.h> to the GLOBALS_SECTION and a call to feenableexcept(EXCEPTION) to TOP_OF_MAIN_SECTION where EXCEPTION is one of the macros to trap specific exceptions. Refer to the man page for fenv or http://pubs.opengroup.org/onlinepubs/009604599/basedefs/fenv.h.html. (Each of the macros FE_DIVBYZERO, FE_INEXACT,  FE_INVALID,  FE_OVERFLOW, and FE_UNDERFLOW  is  defined.)

TOP_OF_MAIN_SECTION
   feenableexcept(FE_DIVBYZERO); // to trap division by zero

GLOBALS_SECTION
  // the order of the include statements is important
  #include <fenv.h> // must appear before admodel.h
  #include <admodel.h>

Build the executable to use a debugger and run the program. When the program crashes, do a back trace (Status->Backtrace in DDD) to find the line in the .cpp file that caused the exception.

Warning: Jim reported some problems using fenv.h and discovered that it not available on some platforms. Apparently there are some unresolved portability problems and this function is missing on all non-glibc platforms: MacOS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, AIX 5.1, HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 11 2010-11, Cygwin 1.7.7, mingw, Interix 3.5, BeOS. See for more information.

 

 

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