Don't pass a value with a side effect to a macro

(closes issue #14176)
Reported by: paraeco
Patches: 
      chan_sip.c.diff uploaded by paraeco (license 658)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@168551 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -7753,6 +7753,8 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
 	}
 
 	if ((fromdomain = strchr(r->username, '@'))) {
+		/* the domain name is just behind '@' */
+		fromdomain++ ;
 		/* We have a domain in the username for registration */
 		snprintf(from, sizeof(from), "<sip:%s>;tag=%s", r->username, p->tag);
 		if (!ast_strlen_zero(p->theirtag))
@@ -7763,7 +7765,7 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
 		/* If the registration username contains '@', then the domain should be used as
 		   the equivalent of "fromdomain" for the registration */
 		if (ast_strlen_zero(p->fromdomain)) {
-			ast_string_field_set(p, fromdomain, ++fromdomain);
+			ast_string_field_set(p, fromdomain, fromdomain);
 		}
 	} else {
 		snprintf(from, sizeof(from), "<sip:%s@%s>;tag=%s", r->username, p->tohost, p->tag);