lib: make union prefixptr C++-compatible

Add a no-op conversion constructor to tell C++ that union prefixptr
accepts any of its member types.

Signed-off-by: David Lamparter <equinox@diac24.net>

diff --git a/lib/prefix.h b/lib/prefix.h
index aaffb1e0c5633e945da3495562ae555aa3418304..231a407cc8f0106ec775c0f5511bbe82e7b65bc8 100644 (file)
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -276,20 +276,29 @@ struct prefix_sg {
  * side, which strips type safety since the cast will accept any pointer
  * type.)
  */
+#ifndef __cplusplus
+#define prefixtype(uname, typename, fieldname) \
+       typename *fieldname;
+#else
+#define prefixtype(uname, typename, fieldname) \
+       typename *fieldname; \
+       uname(typename *x) { this->fieldname = x; }
+#endif
+
 union prefixptr {
-       struct prefix *p;
-       struct prefix_ipv4 *p4;
-       struct prefix_ipv6 *p6;
-       struct prefix_evpn *evp;
-       const struct prefix_fs *fs;
+       prefixtype(prefixptr, struct prefix,      p)
+       prefixtype(prefixptr, struct prefix_ipv4, p4)
+       prefixtype(prefixptr, struct prefix_ipv6, p6)
+       prefixtype(prefixptr, struct prefix_evpn, evp)
+       prefixtype(prefixptr, struct prefix_fs,   fs)
 } __attribute__((transparent_union));
 
 union prefixconstptr {
-       const struct prefix *p;
-       const struct prefix_ipv4 *p4;
-       const struct prefix_ipv6 *p6;
-       const struct prefix_evpn *evp;
-       const struct prefix_fs *fs;
+       prefixtype(prefixconstptr, const struct prefix,      p)
+       prefixtype(prefixconstptr, const struct prefix_ipv4, p4)
+       prefixtype(prefixconstptr, const struct prefix_ipv6, p6)
+       prefixtype(prefixconstptr, const struct prefix_evpn, evp)
+       prefixtype(prefixconstptr, const struct prefix_fs,   fs)
 } __attribute__((transparent_union));
 
 #ifndef INET_ADDRSTRLEN