Debugging Core Files Using HP WDB

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Forcing a Core Dump

WDB enables you to force a core dump of a running process, and analyze the core file.

The dumpcore command forces a core dump and generates a core image file for a process that

is running under the debugger. If no arguments are given, it saves the core image for the current

debugged process in a file named core.<pid>, where <pid> is the process ID number.

Before debugging a forced core dump, you must enter the set live-core 1 command at the

gdb prompt. The set live-core command enables the debugging of a core file created by a

forced core dump. Alternately, you can use the --lcore start-up option to debug a core file

created by a forced core dump.

Saving the Core File to a Specific File Name

You can specify a <corefile-name> as an option in the dumpcore command. This saves the

dumped core file in the specified file, <corefile-name>, instead of core.<pid>.

To specify the filename as an option in the dumpcore command, enter the following command

at the gdb prompt:

(gdb) dumpcore <corefile-name>

Debugging a Core File Created by a Forced Core Dump

To debug a core file that is created by a forced core dump, complete the following steps:

1. To dump the core for a live process, enter the following command at the gdb prompt:

(gdb) dumpcore

For example:

(gdb) run

Starting program: sample

Breakpoint 3, main () at sample.c:1010 b= foo(a);

(gdb) dumpcore

Dumping core to the core file core.24091

(gdb)

2. To analyze the dumped core file, enter one of the following commands:

• At gdb prompt:

(gdb) core [core.<pid>|<corefile-name>]

For example:

(gdb) file sample

Reading symbols from sample...done

(gdb) set live-core 1

(gdb) core core.24091

Core was generated by ’sample’.

#0 main () at sample.c:1010 b = foo(a);

(gdb) backtrace

#0 main () at sample.c:10

(gdb)

(Or)

• At shell prompt:

% gdb --lcore a.out [core.<pid>|<corefile-name>]

For example:

% ./gdb --lcore sample core.24091

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