extcap: fix parameters save in preferences file

Since g583150198b, extcap_arg structures holds a pointer to the current
preference value. So let's not update its value outside of the prefs API
otherwise the call to prefs_set_string_value() with pref_current done
afterwards will never notify the change and the updated value will not
be written in the preference file.
Moreover update ExtcapArgument::resetValue() method to have an empty
string instead of a NULL pointer. Otherwise prefs_set_string_value()
will not notify the change and save the restored default value in the
preference file either.

Change-Id: Ie70e79d471c75e25705c7654e420a7706ebc4032
Reviewed-on: https://code.wireshark.org/review/23308
Petri-Dish: Pascal Quantin <pascal.quantin@gmail.com>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Dario Lombardo <lomato@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

1 files changed, 0 insertions, 3 deletions

diff --git a/extcap.h b/extcap.h
index 013ccdb4fd..ac8993a2c0 100644
--- a/extcap.h
+++ b/extcap.h
@@ -152,9 +152,6 @@ extcap_if_cleanup(capture_options * capture_opts, gchar ** errormsg);
 struct preference *
 extcap_pref_for_argument(const gchar *ifname, struct _extcap_arg * arg);
 
-void
-extcap_pref_store(struct _extcap_arg * arg, const char * newval);
-
 /* Clean up global extcap stuff on program exit */
 void extcap_cleanup(void);