HP 3000 Manuals HP 3000 Manuals
Chapter 13 Debug Module The Debug Module provides a means by which you can describe a debugging algorithm including the conditions under which procedures are to be monitored during the execution of the object program.
NOTE With the exception of debug lines, this module is an obsolete feature of the 1985 ANSI COBOL standard.
The decisions of what to monitor and what information to display on the output device are explicitly yours. The COBOL debug facility simply provides a convenient access to pertinent information. The HP COBOL II Debug Module implements the level 1 characteristics of the ANSI standard Debug Module. It provides a basic debugging capability, including the ability to specify: (a) selective or full procedure monitoring, and (b) optionally compiled debugging statements. The features of the COBOL language that support the Debug Module are: 1. A compile-time switch: WITH DEBUGGING MODE The WITH DEBUGGING MODE clause is written as part of the SOURCE-COMPUTER paragraph. It serves as a compile-time switch over the debugging statements written in the program. When the WITH DEBUGGING MODE clause is specified in a program, all debugging sections and all debugging lines are compiled as specified in that section of the document. When the WITH DEBUGGING MODE clause is not specified, all debugging lines and all debugging sections are compiled as if they were comment lines. 2. An object-time switch: USE FOR DEBUGGING This switch dynamically activates the debugging code inserted by the compiler. This switch cannot be addressed in the program. It is controlled outside the COBOL environment. If the switch is "on", all the effects of the debugging language written in the source program are permitted. If the switch is "off", all the effects of the USE FOR DEBUGGING statement, are inhibited. Recompilation of the source program is required to provide or take away this facility. For information on setting the object-time debug module switch, refer to "System Dependencies" in Appendix H . This object-time switch has no effect on the execution of the object program if the WITH DEBUGGING MODE clause was not specified in the source program at compile time. _________________________________________________________________ NOTE The object-time switch does not control the debugging lines. Recompilation without the "WITH DEBUGGING MODE" clause is necessary to disable the debugging lines. _________________________________________________________________ 3. A special register: DEBUG-ITEM The reserved word DEBUG-ITEM is the name for a special register generated automatically by the compiler. Only one DEBUG-ITEM is allocated per program. The names of the subordinate data items in DEBUG-ITEM are also reserved words. 4. Debugging lines A debugging line is any line with a "D" in column 7. These lines are added anywhere in the program after the OBJECT-COMPUTER paragraph and are used strictly for debugging purposes. Such lines make use of common COBOL statements such as "DISPLAY" in order to monitor program status. The contents of a debugging line must be totally independent of the program itself, so that a syntactically correct program is formed either with or without the debugging lines.