Debugging Dynamic Memory Usage Errors Using HP WDB v6.3 (5900-2181, August 2012)

40 };

(gdb) info heap high-mem

Analyzing heap ...

High memory mark stat

High water mark updated count: 2

No. Total bytes Blocks Address Function

0 100 1 0x4044ff20 func2()

(gdb)

Case 2: The set heap-check high-mem-count <X_number> command stops execution

when the break value has moved <X_number> of times.

$ gdb high

HP gdb 5.6 for HP Itanium (32 or 64 bit) and target HP-UX 11.2x.

Hewlett-Packard Wildebeest 5.5.8 (based on GDB) is covered

by the GNU General Public License. Type "show copying" to

see the conditions to change it and/or distribute copies.

Type "show warranty" for warranty/support.

(gdb) set heap-check on

(gdb) set heap-check high-mem-count 2

(gdb) r

Starting program: high

warning: High water mark

(address = 0x4044ff00 total memory per call site = 100)

#1 func2() at high.c:15

#2 main() at high.c:40

#3 main_opd_entry() from

warning: Use command backtrace (bt) to see the current context.

Ignore top 4 frames belonging to leak detection library of gdb.

__rtc_event (ecode=RTC_NO_ERROR, pointer=0x0, pclist=0x0, size=0)

at ../../../Src/gnu/gdb/infrtc.c:1236

1236 {

Monitoring De-allocations to Detect Double-Frees

The set heap-check free <on/off> command enables you to detect double-frees and frees

with improper arguments.

When this command is enabled, the free() calls are monitored to verify whether the parameters

address valid heap blocks. If an erroneous free() is detected, the debugger stops execution and

reports the error. You can analyze the stack trace to analyze where and how the error occurred.

Example 19 (page 76) illustrates the use of the set heap-check free command.

Monitoring Heap Corruption

WDB enables you to detect the presence of heap-corruption in your application. Table 11 lists the

commands for monitoring heap corruption

Table 11 Commands for Monitoring Heap Corruption

DescriptionCommand

Toggles validation of calls to strcpy(), strncpy(),

memcpy(), memccpy(),memset(), memmove(),

bzero(), and, bcopy()

set heap-check string <on |off>