Specifications

Debugging and Testing Tools
9.1 OpenVMS Debugger
You can locate errors with the debugger by observing and manipulating your
program interactively as it executes. By entering debugger commands at the
terminal, you can perform the following basic debugging techniques:
• Display your program’s source code, identifying where execution is currently
paused
• Browse through the source code to locate points of interest where you might
test for certain conditions
• Set breakpoints to suspend program execution at such points
• Execute your program, including stepping one source line at a time and
restarting from the beginning of the program
• Trace the execution path of the program
• Display the current value of a program variable
• Monitor changes in variables and other program entities during program
execution
• Change the value of a variable and, in some cases, test the modification
without editing the source code, recompiling, and relinking
• Monitor exception conditions and language-specific events, and force events to
occur
These are the basic debugging techniques. After you are satisfied that you have
found the error in the program, you can edit the source code and compile, link,
and execute the corrected version.
9.1.1 Programming Language Support
Most of the languages supported by the debugger are available on both OpenVMS
VAX and OpenVMS AXP, as shown in Table 9–2.
Table 9–2 Language Support on OpenVMS VAX and OpenVMS AXP
On VAX and AXP On VAX Only On AXP Only
Ada Bliss MACRO-64
BASIC DIBOL
C
C++
COBOL
Fortran
Pascal
PL/I
‡VAX MACRO
‡On OpenVMS AXP, VAX MACRO is supported by the MACRO-32 compiler, which converts
VAX MACRO code into AXP machine language code.
The debugger recognizes the syntax, data types, operators, expressions, scoping
rules, and other constructs of a given language. You can change the debugging
context from one language to another during a debugging session with the SET
LANGUAGE command.
9–2