Library: Math, Floating point number support (OMFLOAT) Import: omfloat.xmd

Return type: Boolean Returns:  A value of true when x is NaN; otherwise, a value of false.

Declaration

  export external switch function is-nan value float x

Use is-nan to test a floating point number to determine if it is not a number (NaN). This function returns a switch value of true ("x" is NaN) or false. is-nan provides the only reliable means of determining whether a variable contains a NaN value.

The following "contrived" sample uses is-nan to check for a value that is not a number (NaN). When such a value is found, the message "Error, result is not a number." is displayed.

  import "omfloat.xmd" unprefixed
  process
      local float x initial {3}
      local stream y initial {"A"}
      local float result
      set result to (x / y)

      do when is-nan result
          output "Error, result is not a number. %n"
          halt
      done
  ; Output: "Error, result is not a number."

Other Library Functions    float    is-nan    omfloat-version

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