Totalview® for HPC User Guide : PART I Introduction to Debugging with TotalView : Chapter 1 About TotalView : Stepping and Breakpoints
Stepping and Breakpoints
In TotalView, breakpoints are just a type of action point, and there are four types:
• A breakpoint stops execution of processes and threads that reach it.
• An eval point executes a code fragment when it is reached.
• A barrier point synchronizes a set of threads or processes at a location ("Synchronizing Execution with Barrier Points").
• A watchpoint monitors a location in memory and stops execution when it changes ("Setting Watchpoints").
You can set action points in your program by selecting the boxed line numbers in the Source Code pane of a Process window. A boxed line number indicates that the line generates executable code. A icon appears at the line number to indicate that a breakpoint is set on the line. Selecting the icon clears the breakpoint.
When a program reaches a breakpoint, it stops. You can resume or otherwise control program execution in any of the following ways:
• Use the single-step commands described in “Using Stepping Commands” on page 172.
• Use the set program counter command to resume program execution at a specific source line, machine instruction, or absolute hexadecimal value. See “Setting the Program Counter” on page 179.
• Set breakpoints at lines you choose, and let your program execute to that breakpoint. See “Setting Breakpoints and Barriers” on page 185.
• Set conditional breakpoints that cause a program to stop after it evaluates a condition that you define, for example, “stop when a value is less than eight.” See “Setting Eval Points” on page 204.
 
 
RELATED TOPICS 
 
Detailed information on action points
Stepping commands