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

Example 20 Detecting de-allocation of memory that has not been initialized

Sample Program

$ cat unalloc.c

1 #include<stdio.h>

3 int main() {

5 printf("Starting program\n");

6 char* han;

7 free(han);

8 }

Sample Debugging Session

gdb) set heap-check on

(gdb) file unalloc

Reading symbols from unalloc...done.

(gdb) b main

Breakpoint 1 at 0x2bb4: file unalloc.c, line 5 from unalloc.

(gdb) r

Starting program: unalloc

Breakpoint 1, main () at unalloc.c:5

5 printf("Starting program\n");

(gdb) n

Starting program

7 free(han);

(gdb)

warning: Attempt to free unallocated or already freed

object at 0x70fee070

0x70e78d7c in __rtc_event+0 ()

from /opt/langtools/lib/librtc.sl