Guenter and Joel I appreciate your help but I am coming to the conclusion that the pdf file format is not well enough defined to be able to reliably embed software listings that the reader can copy/paste into a file and then be able to compile the results. I will have to continue as I have done in the past to include a listing in the pdf but also to provide a link to a supplementary online zip file with the source code in text files.
Bob p.s. Guenter, here are the answers to some of the questions in your response: >Does it show up as hyphen or as question mark in the PDF? It is displayed as a '-' in the pdf but copy and paste of the 3 characters in the listing results in x?y with '?' being 3F hex according to my editor. >Which fonts does your PDF use? I do not know how to answer that question. How do I find out what fonts it uses? >What is the result if your listing contains: ... Here is what I get if I enter your list into the listing, create a pdf then copy and paste the text in the listing. 30 ! " # $ % & ' 40 ( ) ? + , ? . / 0 1 50 2 3 4 5 6 7 8 9 : ; 60 < = > ? @ A B C D E 70 F G H I J K L M N O 80 P Q R S T U V W X Y 90 Z [ \ ] ^ _ ` a b c 100 d e f g h i j k l m 110 n o p q r s t u v w 120 x y z { | } ~ 160 ½¢¿¤¥¦?¨ c ? 170 a ?¬ R ?¯°±²³ 180 ´µ¶· ¹ o ?¼½ 190 ¾¾ÀÁÂÃÄÅÆÇ 200 ÈÉÊËÌÍÎÏÐÑ 210 ÒÓÔÕÖ×ØÙÚÛ 220 ÜÝÞÿàáâãäå 230 æçèéêëìíîï 240 ðñòóôõö÷øù 250 úûüýþ¸