Debugging Dynamic Memory Usage Errors Using HP WDB

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Example 9 Monitoring program heap growth

Sample Program

bash-2.05b$ cat heap-size.c

1 #include<stdio.h>

3 int main()

4 {

5 char * cp;

6 printf("Start of the program\n");

7 cp = (char *)malloc(1024 *1024*10);

8 free (cp);

9 cp = (char *)malloc(1024 *1024*8);

10 free (cp);

11 exit(0);

12 }

Sample Debugging Session

bash-2.05b$ /opt/langtools/bin/gdb

HP gdb 5.5.0 for PA-RISC 1.1 or 2.0 (narrow), HP-UX 11.00

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

Hewlett-Packard Wildebeest 5.5.0 (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) file heap-size

Reading symbols from heap-size...done.

(gdb) set heap-check on

(gdb) set heap-check heap-size 8000000

(gdb) b main

Breakpoint 1 at 0x2c04: file heap-size.c, line 6 from heap-size.

(gdb) b 11

Breakpoint 2 at 0x2c60: file heap-size.c, line 11 from heap-size.

(gdb) r

Starting program: heap-size

Breakpoint 1, main () at heap-size.c:6

6 printf("Start of the program\n");

(gdb) c

Continuing.

Start of the program

warning: Attempt to grow the heap at 0x4042c3e0

0x70e78d7c in __rtc_event+0 () from /opt/langtools/lib/librtc.sl

(gdb) bt

#0 0x70e78d7c in __rtc_event+0 () from /opt/langtools/lib/librtc.sl

#1 0x70e7aff4 in malloc_padded+0xa8 () from /opt/langtools/lib/librtc.sl

#2 0x70e7b634 in malloc+0xd4 () from /opt/langtools/lib/librtc.sl

#3 0x2c28 in main () at heap-size.c:7

#4 0x70ee3478 in _start+0xc0 () from /usr/lib/libc.2

(gdb) c

Continuing.

Breakpoint 2, main () at heap-size.c:11

11 exit(0);