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Storage Change Breakpoint dialog box

Restriction: This dialog box is not available when debugging on the AS/400.

Use the Storage Change Breakpoint dialog box to set a new or on AIX or Windows redefine an existing breakpoint that causes execution to stop whenever storage at a specific address changes. Execution stops only if the value changes; if the same data is moved into a storage area, the breakpoint does not trigger a stop.

Caution: If you set a storage change breakpoint for an address that is on the call stack, be sure to remove the breakpoint before leaving the routine associated with it. Otherwise, when you return from the routine, the routine's stack frame will be removed from the stack, but the breakpoint will still be active for that address. Any other routine that gets loaded on the stack will then contain the breakpoint.

Controls and control groupings are described below. Group and subgroup names appear in italics, and control names appear in bold.

Required Parameters Use controls in this group to define where the breakpoint is placed in the program being debugged.
Address or Expression Use this field to enter an address, or an expression that evaluates to a valid address.
Bytes to Monitor Use this field to specify a value to tell the debugger the number of bytes you want it to monitor.

The valid range depends on the operating system where you are debugging your program.
Optional Parameters Provide additional control over when breakpoints are triggered.
Thread This selection list lets you choose what threads to set the breakpoint in. To select a thread ID from the list, highlight the thread where you want to set the breakpoint. This list is available only on platforms that support multithreaded programs.
Frequency Use the Frequency controls to tell the debugger when to stop on a breakpoint and when to skip it. The debugger keeps track of how many times each breakpoint is encountered. The fields in this section tell the debugger on which encounter of a breakpoint the debugger should first stop, how often it should stop, and on which encounter the debugger should no longer stop.
From Enter the first breakpoint encounter you want the debugger to stop on. For example, if you want the debugger to skip over the breakpoint the first five times it is encountered, enter "6".
To Enter the last breakpoint encounter you want the debugger to stop on. For example, if you want it to start ignoring the breakpoint after the 20th encounter, enter "20". To have it always stop on the breakpoint, enter "Infinity".
Every Enter the frequency with which you want the debugger to stop on this breakpoint. For example, if you want it to stop on only one out of every four it encounters, enter "4".
Push-buttons
OK Creates the storage change breakpoint using the settings you specified, then closes the Storage Change Breakpoint dialog box.
Set Creates the storage change breakpoint using the settings you specified, but keeps the Storage Change Breakpoint dialog box open so you can create more breakpoints.
Default Saves the settings in the Optional Parameters group for use as default settings when you next set a new breakpoint.
Cancel Closes the Storage Change Breakpoint dialog box without creating a new breakpoint.
Help Displays this help panel.