Action Points

Action points tell the CLI that it should stop a program's execution. You can specify four different kinds of action points:

• A breakpoint (see dbreak) stops the process when the program reaches a location in the source code.
   
• A watchpoint (see dwatch) stops the process when the value of a variable is changed.
   
• A barrier point (see dbarrier), as its name suggests, effectively prevents processes from proceeding beyond a point until other processes arrive. This gives you a method for synchronizing the activities of processes. (Note that barriers can only be applied to entire processes, not to individual threads.)
   
• An evaluation point (see dbreak) lets you programmatically evaluate the state of the process or variable when execution reaches a location in the source code. Evaluation points typically do not stop the process; instead, they perform an action.

Note:   Extensive information on action points can be found in the TotalView User's Guide.

Each action point is associated with an action point identifier. You use these identifiers when you need to refer to the action point. Like process and thread identifiers, action point identifiers are assigned numbers as they are created. The ID of the first action point created is 1. The second ID is 2, and so on. These numbers are never reused during a debugging session.

The CLI and TotalView only let you assign one action point to a source code line. However, neither limits the complexity of an action point.