Debugging Dynamic Memory Usage Errors Using HP WDB (5900-1474; WDB 6.2; January 2011)

Memory Checking Analysis for User Defined Memory Management Routines
Many user applications have their own memory management routines. These custom
allocator routines are either user defined or sometimes wrappers to the default memory
management routines. Memory checking features have been extended for user defined
memory management routines. Memory leak, prole of heap memory, or memory errors
can be obtained for user defined memory management routines.
Following are the limitations for user-defined memory management routines:
• This feature routes to default memory routines instead of calling user defined memory
management routines to obtain memory analysis.
• This feature is not supported in batch mode and attach mode debugging.
Memory-Debugging Features of WDB
WDB supports the following memory-debugging features:
• Heap Profiling features
• Leak Profiling feature
• Error Injection features
• Event Monitoring features
In addition to these features, HP WDB provides the following generic commands for
memory debugging:
Table 3 Generic Commands for Memory Checking
DescriptionCommand
Toggles the setting of commands for detecting leaks,
bounds, double frees, and heap profiling.
set heap-check <on/off>
Displays the current settings for memory checkingshow heap-check
NOTE: GDB reports an incorrect stack trace after dlclose or shl_unload, and a
subsequent dlopen or shl_load. The leaks are displayed erroneously when the memory
address range overlaps between the newly loaded shared library, and the recently
unloaded shared library.
Workaround: Place a breakpoint at dlclose or shl_unload, and enter the info
leaks command to view the leaks accurately when a shared library is unloaded.
Heap Profiling
You can profile the heap usage in an application by using WDB. The heap-profiling
feature enables you to analyze the influence of algorithms and data structures on heap
usage and tune the memory requirements of an application.
12