+
+ /* We have to allow for a named reference to a duplicated name (this
+ cannot be determined until the second pass). This needs an extra
+ 16-bit data item. */
+
+ *lengthptr += IMM2_SIZE;
+
+ /* If this is a forward reference and we are within a (?|...) group,
+ the reference may end up as the number of a group which we are
+ currently inside, that is, it could be a recursive reference. In the
+ real compile this will be picked up and the reference wrapped with
+ OP_ONCE to make it atomic, so we must space in case this occurs. */
+
+ /* In fact, this can happen for a non-forward reference because
+ another group with the same number might be created later. This
+ issue is fixed "properly" in PCRE2. As PCRE1 is now in maintenance
+ only mode, we finesse the bug by allowing more memory always. */
+
+ *lengthptr += 2 + 2*LINK_SIZE;
+
+ /* It is even worse than that. The current reference may be to an
+ existing named group with a different number (so apparently not
+ recursive) but which later on is also attached to a group with the
+ current number. This can only happen if $(| has been previous
+ encountered. In that case, we allow yet more memory, just in case.
+ (Again, this is fixed "properly" in PCRE2. */
+
+ if (cd->dupgroups) *lengthptr += 4 + 4*LINK_SIZE;
+
+ /* Otherwise, check for recursion here. The name table does not exist
+ in the first pass; instead we must scan the list of names encountered
+ so far in order to get the number. If the name is not found, leave
+ the value of recno as 0 for a forward reference. */
+
+ else
+ {
+ ng = cd->named_groups;
+ for (i = 0; i < cd->names_found; i++, ng++)
+ {
+ if (namelen == ng->length &&
+ STRNCMP_UC_UC(name, ng->name, namelen) == 0)
+ {
+ open_capitem *oc;
+ recno = ng->number;
+ if (is_recurse) break;
+ for (oc = cd->open_caps; oc != NULL; oc = oc->next)
+ {
+ if (oc->number == recno)
+ {
+ oc->flag = TRUE;
+ break;
+ }
+ }
+ }
+ }
+ }