Setting a storage change breakpoint

Restrictions: Storage change breakpoints are not supported on AIX.

ngjava.gif (225 bytes) Storage change breakpoints are not available when debugging interpreted Java programs. They are available when debugging High Performance Compiled (HPC) Java programs.

Storage change breakpoints halt execution of your program whenever storage at a specific address is changed. For example, if a byte being watched contains X'40' and the program writes X'40' to that byte, the storage change breakpoint is not triggered. If the program writes X'41', the storage change breakpoint is triggered.

To set a storage change breakpoint from the Breakpoints menu:

  1. Select Breakpoints > Set Storage Change from the menu bar.
  2. Enter an address or expression that evaluates to an address in the Address or Expression field.
    ngclang.gif (151 bytes)ngcpp.gif (202 bytes) Tip: You can enter the address of a variable by specifying the variable name preceded by an ampersand (&).
  3. Specify the number of bytes to be monitored in the Bytes to Monitor field.
  4. Set any optional parameters that you want for the breakpoint.
  5. Click OK to set the breakpoint and dismiss the Storage Change Breakpoint dialog. Alternatively, use the Set button to set the breakpoint without dismissing the Storage Change Breakpoint dialog.

Caution: If you set a storage change breakpoint for any 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. Any other routine that gets loaded on the stack will then contain the breakpoint.

[Related Concepts]
Breakpoints

Related Tasks
Setting multiple breakpoints
Setting a watchpoint
Setting a conditional breakpoint
Modifying breakpoint properties
Enabling and disabling breakpoints
Deleting a breakpoint
Viewing breakpoints