Debugging with GDB Manual The GNU Source-Level Debugger (769148-001, March 2014)

1. If the linker version is earlier than B.11.19, link with /opt/langtools/lib/pa20_ 64/
librtc.sl for PA-64 programs. For a 32-bit program, you must link with /opt/langtools/
lib/librtc.sl.
If the dynamic linker version is B.11.19 or later, skip this step because HP WDB automatically
loads the librtc.sl library.
2. Turn on profiling with the set heap-check on command:
(gdb) set heap-check on
3. Set a breakpoint:
(gdb) b myfunction
4. When the program is stopped at a breakpoint, use the info heap command:
(gdb) info heap
Analyzing heap ...done
Actual Heap Usage:
Heap Start = 0x40408000
Heap End = 0x4041a900
Heap Size = 76288 bytes
Outstanding Allocations:
41558 bytes allocated in 28 blocks
No. Total bytes Blocks Address Function
0 34567 1 0x40411000 foo()
1 4096 1 0x7bd63000 bar()
2 1234 1 0x40419710 baz()
3 245 8 0x404108b0 boo()
[...]
The display shows the currently allocated heap blocks. Any blocks that have been allocated
and already freed are not listed.
To look at a specific allocation, specify the allocation number with the info heap command:
(gdb) info heap 1
4096 bytes at 0x7bd63000 (9.86% of all bytes allocated)
in bar () at test.c:108
in main () at test.c:17
in _start ()
in $START$ ()
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 has been extended for user defined memory management routines.
Memory leak, profile of heap memory or memory errors can be obtained for user defined memory
management routines.
Limitations:
• 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.
Commands to track the change in data segment value
The high water mark records the number of times the brk() value changes. The following
commands are supported:
info heap high-mem Displays the number of times brk() value changes for a
given run.
132 HP-UX Configuration-Specific Information