Setting Breakpoints and Traces

When an event occurs, dbx allows you to stop a process, execute arbitrary commands, or print information. The simplest example of an event is a breakpoint. Examples of other events are faults, signals, system calls, calls to dlopen(), and data changes.

A trace displays information about an event in your program, such as a change in the value of a variable. Although a trace’s behavior is different from that of a breakpoint, traces and breakpoints share similar event handlers (see Event Handlers).

This chapter describes how to set, clear, and list breakpoints and traces. For complete information on the event specifications you can use in setting breakpoints and traces, see Setting Event Specifications.

This chapter is organized into the following sections:

• Setting Breakpoints

• Setting Filters on Breakpoints

• Tracing Execution

• Setting a when Breakpoint at a Line

• Setting Breakpoints in Dynamically Loaded Libraries

• Listing and Clearing Breakpoints

• Enabling and Disabling Breakpoints

• Efficiency Considerations