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

Example 14 Scrambling a memory block on de-allocation

Sample Program

$ cat scramble.c

1 #include <stdio.h>

2 #include <malloc.h>

4 int

5 main ()

6 {

7 char **tp;

8 tp = malloc (100);

9 printf ("Batch RTC test over, *tp=%p.\n", *tp);

10 fflush(stdout);

11 free(tp);

12 exit (0);

13 }

Sample Debugging Session

$ gdb scramble

HP gdb 5.5 for PA-RISC 1.1 or 2.0 (narrow), HP-UX 11.00

and target hppa1.1-hp-hpux11.00.

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 scramble on

(gdb) b main

Breakpoint 1 at 0x295c: file scramble.c, line 8 from scramble.

(gdb) r

Starting program: scramble

Breakpoint 1, main () at scramble.c:8

8 tp = malloc (100);

(gdb) n

9 printf ("Batch RTC test over, *tp=%p.\n", *tp);

(gdb) p *tp

$1 = 0xfeedface <Error reading address 0xfeedface: Bad address>

Open-files reporting

From version 6.2 onwards, HP WDB enables you to obtain a report containing a list of file

descriptors corresponding to files open by the application at the point of its exit. The report not

only provides you the names and types of those files, but also details such as backtraces and

function names at the point of the files being opened. This enables you to identify potential file

descriptor leaks in the application.

Memory-Debugging Features of WDB 45