4. Viewing and Navigating To Code
5. Controlling Program Execution
6. Setting Breakpoints and Traces
Setting a stop Breakpoint at a Line of Source Code
Setting a stop Breakpoint in a Function
Setting Multiple Breaks in C++ Programs
Setting Breakpoints in Member Functions of Different Classes
Setting Breakpoints in All Member Functions of a Class
Setting Multiple Breakpoints in Nonmember Functions
Setting Breakpoints in Objects
Setting Data Change Breakpoints
Stopping Execution When an Address Is Accessed
Stopping Execution When Variables Change
Stopping Execution on a Condition
Setting Filters on Breakpoints
Using the Return Value of a Function Call as a Filter
Setting Data Change Breakpoints on Local Variables
Using a Filter With a Conditional Event
Setting a when Breakpoint at a Line
Setting Breakpoints in Dynamically Loaded Libraries
Listing and Clearing Breakpoints
Listing Breakpoints and Traces
Deleting Specific Breakpoints Using Handler ID Numbers
Enabling and Disabling Breakpoints
8. Evaluating and Displaying Data
11. Debugging Multithreaded Applications
16. Debugging Fortran Using dbx
17. Debugging a Java Application With dbx
18. Debugging at the Machine-Instruction Level
19. Using dbx With the Korn Shell
Tracing collects information about what is happening in your program and displays it. If a program arrives at a breakpoint created with a trace command, the program halts and an event-specific trace information line is emitted, then the program continues.
A trace displays each line of source code as it is about to be executed. In all but the simplest programs, this trace produces volumes of output.
A more useful trace applies a filter to display information about events in your program. For example, you can trace each call to a function, every member function of a given name, every function in a class, or each exit from a function. You can also trace changes to a variable.
Set a trace by typing a trace command at the command line. The basic syntax of the trace command is:
trace event-specification [ modifier ]
For the complete syntax of the trace command, see trace Command.
The information a trace provides depends on the type of event associated with it (see Setting Event Specifications).
Often trace output goes by too quickly. The dbx environment variable trace_speed lets you control the delay after each trace is printed. The default delay is 0.5 seconds.
To set the interval in seconds between execution of each line of code during a trace, type:
dbxenv trace_speed number
You can direct the output of a trace to a file using the -file filename option. For example, the following command direct trace output to the file trace1:
(dbx) trace -file trace1
To revert trace output to standard output use - for filename. Trace output is always appended to filename. It is flushed whenever dbx prompts and when the application has exited. The filename is always re-opened on a new run or resumption after an attach.