OPENLDAP client API option to capture the communication traces in a file

How client can leverage this LBER_OPT_LOG_PRINT_FILE option to redirect the log to the file? I had tried setting this option after ldap_initalize from the client end. But still, I couldn't get any traces in the supplied logfile. The traces works fine in the console mode with DEBUG_OPENLDAP. But they seem not to be working with this.

Could you suggest any other approach or configuration which can be used to capture the underlying OpenLDAP communication from the client-side?

@hyc/@openldap-technical-owner@openldap.org: Would appreciate it if you can share any thoughts?