[svn-r12528] Added User-Defined links to the library.

Users can create external links using H5L_create_external().  These links
point to an object in another HDF5 file.  Users can alter the behavior of
external links or create new kinds of links by registering callbacks
using the H5L interface.

Added tests, tools support, etc.

Also a number of other, minor changes have been made (some restructuring of
the H5L interface, for instance).

Additional documentation and examples are forthcoming.

5 files changed, 324 insertions, 45 deletions

diff --git a/tools/h5dump/h5dump.c b/tools/h5dump/h5dump.c
index 4bd388a..7a49950 100644
--- a/tools/h5dump/h5dump.c
+++ b/tools/h5dump/h5dump.c
@@ -271,6 +271,10 @@ static const h5dump_header_t standardformat = {
     "",				/*dataend */
     SOFTLINK,			/*softlinkbegin */
     "",				/*softlinkend */
+    EXTLINK,			/*extlinkbegin */
+    "",				/*extlinkend */
+    UDLINK,			/*udlinkbegin */
+    "",				/*udlinkend */
     SUBSET,			/*subsettingbegin */
     "",				/*subsettingend */
     START,			/*startbegin */
@@ -300,6 +304,10 @@ static const h5dump_header_t standardformat = {
     "}",			/*datablockend */
     "{",			/*softlinkblockbegin */
     "}",			/*softlinkblockend */
+    "{",			/*extlinkblockbegin */
+    "}",			/*extlinkblockend */
+    "{",			/*udlinkblockbegin */
+    "}",			/*udlinkblockend */
     "{",			/*strblockbegin */
     "}",			/*strblockend */
     "{",			/*enumblockbegin */
@@ -1398,6 +1406,7 @@ dump_all(hid_t group, const char *name, void * op_data)
     hid_t       obj;
     char       *obj_path = NULL;        /* Full path of object */
     H5G_stat_t  statbuf;
+    H5L_linkinfo_t linfo;              /* Link information */
     herr_t      ret = SUCCEED;
 
     /* Stat the object */
@@ -1407,6 +1416,12 @@ dump_all(hid_t group, const char *name, void * op_data)
         ret = FAIL;
         goto done;
     } /* end if */
+    if(H5Lget_linkinfo(group, name, &linfo, H5P_DEFAULT) < 0) {
+        error_msg(progname, "unable to get object information\n");
+        d_status = EXIT_FAILURE;
+        ret = FAIL;
+        goto done;
+    } /* end if */
 
     if (*(int *)op_data != H5G_UNKNOWN && statbuf.type != *(int *) op_data)
         goto done;
@@ -1433,7 +1448,7 @@ dump_all(hid_t group, const char *name, void * op_data)
                 indentation(indent + COL);
             }
 
-            if (H5Gget_linkval(group, name, statbuf.linklen, targbuf) < 0) {
+            if (H5Lget_linkval(group, name, statbuf.linklen, targbuf, H5P_DEFAULT) < 0) {
                 error_msg(progname, "unable to get link value\n");
                 d_status = EXIT_FAILURE;
                 ret = FAIL;
@@ -1516,7 +1531,128 @@ dump_all(hid_t group, const char *name, void * op_data)
             HDfree(targbuf);
             break;
         }
+        case H5G_UDLINK:
+        {
+            indentation(indent);
+            switch(linfo.linkclass)
+            {
+              case H5L_LINK_EXTERNAL:
+              {
+                char *targbuf;
+                char *filename;
+                char *targname;
+                targbuf = HDmalloc(statbuf.linklen);
+                HDassert(targbuf);
+                if (!doxml) {
+                    begin_obj(dump_header_format->extlinkbegin, name,
+                            dump_header_format->extlinkblockbegin);
+                }
+                if (H5Lget_linkval(group, name, statbuf.linklen, targbuf, H5P_DEFAULT) < 0) {
+                    error_msg(progname, "unable to get external link value\n");
+                    d_status = EXIT_FAILURE;
+                    ret = FAIL;
+                } else {
+                    if(H5Lunpack_elink_val(targbuf, &filename, &targname) < 0) {
+                      error_msg(progname, "unable to unpack external link value\n");
+                      d_status = EXIT_FAILURE;
+                      ret = FAIL;
+                    } else {
+                      if (!doxml) {
+                          indentation(indent + COL);
+                          printf("LINKCLASS %d\n", linfo.linkclass);
+                          indentation(indent + COL);
+                          printf("TARGETFILE \"%s\"\n", filename);
+                          indentation(indent + COL);
+                          printf("TARGETPATH \"%s\"\n", targname);
+                      }
+                      else /* XML */
+                      {
+                        char linkxid[100];
+                        char parentxid[100];
+                        char *t_name = xml_escape_the_name(name);
+                        char *t_prefix = xml_escape_the_name(HDstrcmp(prefix,"") ? prefix : "/");
+                        char *t_obj_path = xml_escape_the_name(obj_path);
+                        char *t_filename = xml_escape_the_name(filename);
+                        char *t_targname = xml_escape_the_name(targname);
+
+                        /* Create OBJ-XIDs for the parent and object */
+                        xml_name_to_XID(t_obj_path, linkxid, sizeof(linkxid), 1);
+                        xml_name_to_XID(prefix, parentxid, sizeof(parentxid), 1);
+
+                            printf("<%sExternalLink LinkName=\"%s\" "
+                                  "OBJ-XID=\"%s\" "
+                                  "H5SourcePath=\"%s\" "
+                                  "TargetFilename=\"%s\"  "
+                                  "TargetPath=\"%s\"  "
+                                  "Parents=\"%s\" H5ParentPaths=\"%s\" />\n",
+                                    xmlnsprefix,
+                                    t_name,         /* LinkName */
+                                    linkxid,        /* OBJ-XID */
+                                    t_obj_path,     /* H5SourcePath */
+                                    filename,       /* TargetFilename */
+                                    targname,       /* TargetPath*/
+                                    parentxid,      /* Parents */
+                                    t_prefix);      /* H5ParentPaths */
+                        HDfree(t_prefix);
+                        HDfree(t_name);
+                        HDfree(t_filename);
+                        HDfree(t_targname);
+                        HDfree(t_obj_path);
+                      }
+                    }
+                }
+                if (!doxml) {
+                    end_obj(dump_header_format->extlinkend,
+                            dump_header_format->extlinkblockend);
+                }
+                HDfree(targbuf);
+              }
+              break;
+              default:
+                  if (!doxml) {
+                      begin_obj(dump_header_format->udlinkbegin, name,
+                                dump_header_format->udlinkblockbegin);
+                      indentation(indent + COL);
+                  }
+                  if (!doxml) {
+                      printf("LINKCLASS %d\n", linfo.linkclass);
+                  }
+                  else /* XML */
+                  {
+                    char linkxid[100];
+                    char parentxid[100];
+                    char *t_name = xml_escape_the_name(name);
+                    char *t_prefix = xml_escape_the_name(HDstrcmp(prefix,"") ? prefix : "/");
+                    char *t_obj_path = xml_escape_the_name(obj_path);
+
+                    /* Create OBJ-XIDs for the parent and object */
+                    xml_name_to_XID(t_obj_path, linkxid, sizeof(linkxid), 1);
+                    xml_name_to_XID(prefix, parentxid, sizeof(parentxid), 1);
 
+                        printf("<%sUserDefined LinkName=\"%s\" "
+                               "OBJ-XID=\"%s\" "
+                               "H5SourcePath=\"%s\" "
+                               "LinkClass=\"%d\"  "
+                               "Parents=\"%s\" H5ParentPaths=\"%s\" />\n",
+                                xmlnsprefix,
+                                t_name,             /* LinkName */
+                                linkxid,            /* OBJ-XID */
+                                t_obj_path,         /* H5SourcePath */
+                                linfo.linkclass,    /* LinkClass */
+                                parentxid,          /* Parents */
+                                t_prefix);          /* H5ParentPaths */
+                    HDfree(t_prefix);
+                    HDfree(t_name);
+                    HDfree(t_obj_path);
+                  }
+                  if (!doxml) {
+                      indentation(indent);
+                      end_obj(dump_header_format->udlinkend,
+                              dump_header_format->udlinkblockend);
+                  }
+            }
+            break;
+          }
         case H5G_GROUP:
             if ((obj = H5Gopen(group, name)) < 0) {
                 error_msg(progname, "unable to dump group \"%s\"\n", name);
@@ -2003,7 +2139,7 @@ dump_data(hid_t obj_id, int obj_data, struct subset_t *sset, int display_ai)
 
     /* Print all the values. */
     if (obj_data == DATASET_DATA) {
-        hid_t       f_type = H5Dget_type(obj_id); 
+        hid_t       f_type = H5Dget_type(obj_id);
         char        string_prefix[64];
         h5tool_format_t    string_dataformat;
 
@@ -2683,7 +2819,7 @@ set_output_file(const char *fname, int is_bin)
   else
    rawdatastream = NULL;
  }
- 
+
  /* binary output */
  if (is_bin)
  {
@@ -2699,7 +2835,7 @@ set_output_file(const char *fname, int is_bin)
    return 0;
   }
  }
- 
+
  return -1;
 }
 
@@ -3044,7 +3180,7 @@ handle_groups(hid_t fid, char *group, void UNUSED * data)
 /*-------------------------------------------------------------------------
  * Function:    handle_links
  *
- * Purpose:     Handle the links from the command.
+ * Purpose:     Handle soft or UD links from the command.
  *
  * Return:      void
  *
@@ -3059,18 +3195,24 @@ static void
 handle_links(hid_t fid, char *links, void UNUSED * data)
 {
     H5G_stat_t  statbuf;
+    H5L_linkinfo_t linfo;
+    char * elink_file;
+    char * elink_path;
 
     if (H5Gget_objinfo(fid, links, FALSE, &statbuf) < 0) {
         error_msg(progname, "unable to get obj info from \"%s\"\n", links);
         d_status = EXIT_FAILURE;
-    } else if (statbuf.type == H5G_LINK) {
+    } else if (H5Lget_linkinfo(fid, links, &linfo, H5P_DEFAULT) < 0) {
+        error_msg(progname, "unable to get link info from \"%s\"\n", links);
+        d_status = EXIT_FAILURE;
+    } else if (statbuf.type == H5G_LINK) {    /* Soft link */
         char *buf = HDmalloc(statbuf.linklen);
 
         begin_obj(dump_header_format->softlinkbegin, links,
                   dump_header_format->softlinkblockbegin);
         indentation(COL);
 
-        if (H5Gget_linkval(fid, links, statbuf.linklen, buf) >= 0) {
+        if (H5Lget_linkval(fid, links, statbuf.linklen, buf, H5P_DEFAULT) >= 0) {
             printf("LINKTARGET \"%s\"\n", buf);
         } else {
             error_msg(progname, "h5dump error: unable to get link value for \"%s\"\n",
@@ -3080,7 +3222,45 @@ handle_links(hid_t fid, char *links, void UNUSED * data)
 
         end_obj(dump_header_format->softlinkend,
                 dump_header_format->softlinkblockend);
-
+        HDfree(buf);
+    } else if (statbuf.type == H5G_UDLINK) {    /* User-defined link */
+        char *buf = HDmalloc(statbuf.linklen);
+        begin_obj(dump_header_format->udlinkbegin, links,
+                  dump_header_format->udlinkblockbegin);
+        indentation(COL);
+        switch(linfo.linkclass) {
+          case H5L_LINK_EXTERNAL:
+              begin_obj(dump_header_format->extlinkbegin, links,
+                        dump_header_format->extlinkblockbegin);
+              if (H5Lget_linkval(fid, links, statbuf.linklen, buf, H5P_DEFAULT) >= 0) {
+                  if(H5Lunpack_elink_val(buf, &elink_file, &elink_path)>=0) {
+                      indentation(COL);
+                      printf("LINKCLASS %d\n", linfo.linkclass);
+                      indentation(COL);
+                      printf("TARGETFILE \"%s\"\n", elink_file);
+                      indentation(COL);
+                      printf("TARGETPATH \"%s\"\n", elink_path);
+                  } else {
+                      error_msg(progname, "h5dump error: unable to unpack external link value for \"%s\"\n",
+                                links);
+                      d_status = EXIT_FAILURE;
+                  }
+              } else {
+                  error_msg(progname, "h5dump error: unable to get external link value for \"%s\"\n",
+                            links);
+                  d_status = EXIT_FAILURE;
+              }
+              end_obj(dump_header_format->extlinkend,
+                dump_header_format->extlinkblockend);
+          break;
+          default:
+              begin_obj(dump_header_format->udlinkbegin, links,
+                        dump_header_format->udlinkblockbegin);
+              indentation(COL);
+              printf("LINKCLASS %d\n", linfo.linkclass);
+              end_obj(dump_header_format->udlinkend,
+                      dump_header_format->udlinkblockend);
+        }
         HDfree(buf);
     } else {
         error_msg(progname, "\"%s\" is not a link\n", links);
@@ -5054,7 +5234,8 @@ xml_dump_group(hid_t gid, const char *name)
                 H5Giterate(gid, ".", NULL, dump_all, (void *) &xtype);
                 xtype = H5G_LINK;
                 H5Giterate(gid, ".", NULL, dump_all, (void *) &xtype);
-
+                xtype = H5G_UDLINK;
+                H5Giterate(gid, ".", NULL, dump_all, (void *) &xtype);
             }
             free(t_name);
             free(grpxid);
@@ -5114,7 +5295,8 @@ xml_dump_group(hid_t gid, const char *name)
   	H5Giterate(gid, ".", NULL, dump_all, (void *) &xtype);
 	xtype = H5G_LINK;
 	H5Giterate(gid, ".", NULL, dump_all, (void *) &xtype);
-
+	xtype = H5G_UDLINK;
+	H5Giterate(gid, ".", NULL, dump_all, (void *) &xtype);
     }
 
     indent -= COL;
diff --git a/tools/h5dump/h5dump.h b/tools/h5dump/h5dump.h
index dbc5de9..08aa527 100644
--- a/tools/h5dump/h5dump.h
+++ b/tools/h5dump/h5dump.h
@@ -45,6 +45,8 @@
 #define S_SIMPLE        "SIMPLE"
 #define S_NULL          "NULL"
 #define SOFTLINK        "SOFTLINK"
+#define EXTLINK         "EXTERNAL_LINK"
+#define UDLINK          "USERDEFINED_LINK"
 #define STORAGELAYOUT   "STORAGELAYOUT"
 #define START           "START"
 #define STRIDE          "STRIDE"
@@ -91,6 +93,10 @@ typedef struct h5dump_header_t {
     const char *dataend;
     const char *softlinkbegin;
     const char *softlinkend;
+    const char *extlinkbegin;
+    const char *extlinkend;
+    const char *udlinkbegin;
+    const char *udlinkend;
     const char *subsettingbegin;
     const char *subsettingend;
     const char *startbegin;
@@ -120,6 +126,10 @@ typedef struct h5dump_header_t {
     const char *datablockend;
     const char *softlinkblockbegin;
     const char *softlinkblockend;
+    const char *extlinkblockbegin;
+    const char *extlinkblockend;
+    const char *udlinkblockbegin;
+    const char *udlinkblockend;
     const char *strblockbegin;
     const char *strblockend;
     const char *enumblockbegin;
diff --git a/tools/h5dump/h5dumpgentest.c b/tools/h5dump/h5dumpgentest.c
index 89652f2..3a5272a 100644
--- a/tools/h5dump/h5dumpgentest.c
+++ b/tools/h5dump/h5dumpgentest.c
@@ -79,7 +79,8 @@
 #define FILE50  "taindices.h5"
 #define FILE51  "tlonglinks.h5"
 #define FILE52  "tldouble.h5"
-
+#define FILE53  "textlink.h5"
+#define FILE54  "tudlink.h5"
 
 
 
@@ -120,6 +121,27 @@ const H5Z_class_t H5Z_MYFILTER[1] = {{
 }};
 
 
+/* A UD link traversal function.  Shouldn't actually be called. */
+static hid_t UD_traverse(UNUSED const char * link_name, UNUSED hid_t cur_group,
+     UNUSED void * udata, UNUSED size_t udata_size, UNUSED hid_t lapl_id)
+{
+return -1;
+}
+
+#define MY_LINKCLASS 187
+
+const H5L_link_class_t UD_link_class[1] = {{
+    H5L_LINK_CLASS_T_VERS,    /* H5L_link_class_t version       */
+    MY_LINKCLASS,             /* Link type id number            */
+    "UD link class",          /* name for debugging             */
+    NULL,                     /* Creation callback              */
+    NULL,                     /* Move/rename callback           */
+    NULL,                     /* Copy callback                  */
+    UD_traverse,              /* The actual traversal function  */
+    NULL,                     /* Deletion callback              */
+    NULL                      /* Query callback                 */
+}};
+
 
 #define LENSTR  50
 #define LENSTR2  11
@@ -403,8 +425,8 @@ static void gent_softlink(void)
 
     fid = H5Fcreate(FILE4, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
     root = H5Gopen (fid, "/");
-    H5Glink (root, H5G_LINK_SOFT, "somevalue", "slink1");
-    H5Glink (root, H5G_LINK_SOFT, "linkvalue", "slink2");
+    H5Glink (root, H5L_LINK_SOFT, "somevalue", "slink1");
+    H5Glink (root, H5L_LINK_SOFT, "linkvalue", "slink2");
 
     H5Gclose(root);
     H5Fclose(fid);
@@ -441,19 +463,48 @@ static void gent_hardlink(void)
     H5Dclose(dataset);
 
     group = H5Gcreate (fid, "/g1", 0);
-    H5Glink (group, H5G_LINK_HARD, "/dset1", "dset2");
+    H5Glink (group, H5L_LINK_HARD, "/dset1", "dset2");
     H5Gclose(group);
 
     group = H5Gcreate (fid, "/g2", 0);
-    H5Glink (group, H5G_LINK_HARD, "/dset1", "dset3");
+    H5Glink (group, H5L_LINK_HARD, "/dset1", "dset3");
     H5Gclose(group);
 
     group = H5Gopen(fid, "/g1");
-    H5Glink (group, H5G_LINK_HARD, "/g2", "g1.1");
+    H5Glink (group, H5L_LINK_HARD, "/g2", "g1.1");
     H5Gclose(group);
     H5Fclose(fid);
 }
 
+static void gent_extlink(void)
+{
+    hid_t fid;
+
+    /* This external link will dangle, but that's okay */
+    fid = H5Fcreate(FILE53, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    H5Lcreate_external("filename", "objname", fid, "extlink1", H5P_DEFAULT, H5P_DEFAULT);
+    H5Lcreate_external("anotherfile", "anotherobj", fid, "extlink2", H5P_DEFAULT, H5P_DEFAULT);
+
+    H5Fclose(fid);
+}
+
+static void gent_udlink(void)
+{
+    hid_t fid;
+    char buf[4];
+
+    H5Lregister(UD_link_class);
+
+    /* This ud link will dangle, but that's okay */
+    fid = H5Fcreate(FILE54, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    H5Lcreate_ud(fid, "udlink1", MY_LINKCLASS, NULL, 0, H5P_DEFAULT, H5P_DEFAULT);
+    strcpy(buf, "foo");
+    H5Lcreate_ud(fid, "udlink2", MY_LINKCLASS, buf, 4, H5P_DEFAULT, H5P_DEFAULT);
+
+    H5Fclose(fid);
+}
+
+
 /*
                /
      /     |       \     \
@@ -830,9 +881,9 @@ static void gent_compound_dt2(void) {       /* test compound data type */
 / : g1  g2  attr1  attr2
 g1 : g1.1  g1.2
 g1.1 : dset1.1.1(attr1, attr2)   dset1.1.2
-g1.2 : g1.2.1
+g1.2 : g1.2.1 extlink
 g1.2.1 : slink
-g2 : dset2.1  dset2.2
+g2 : dset2.1  dset2.2 udlink
 
 */
 
@@ -926,9 +977,12 @@ float dset2_1[10], dset2_2[3][5];
 
   H5Gclose(group);
 
+  /* external link */
+  H5Lcreate_external("somefile", "somepath", fid, "/g1/g1.2/extlink", H5P_DEFAULT, H5P_DEFAULT);
+
   /* soft link */
   group = H5Gopen (fid, "/g1/g1.2/g1.2.1");
-  H5Glink (group, H5G_LINK_SOFT, "somevalue", "slink");
+  H5Glink (group, H5L_LINK_SOFT, "somevalue", "slink");
   H5Gclose(group);
 
   group = H5Gopen (fid, "/g2");
@@ -956,6 +1010,10 @@ float dset2_1[10], dset2_2[3][5];
 
   H5Gclose(group);
 
+  /* user-defined link */
+  H5Lregister(UD_link_class);
+  H5Lcreate_ud(fid, "/g2/udlink", MY_LINKCLASS, NULL, 0, H5P_DEFAULT, H5P_DEFAULT);
+
   H5Fclose(fid);
 
 }
@@ -981,8 +1039,8 @@ hid_t fid, group;
   group = H5Gcreate (fid, "/g2", 0);
   H5Gclose(group);
 
-  H5Glink(fid, H5G_LINK_HARD, "/g2", "/g1/g1.1");
-  H5Glink(fid, H5G_LINK_HARD, "/g1", "/g2/g2.1");
+  H5Glink(fid, H5L_LINK_HARD, "/g2", "/g1/g1.1");
+  H5Glink(fid, H5L_LINK_HARD, "/g1", "/g2/g2.1");
 
   H5Fclose(fid);
 }
@@ -1001,10 +1059,10 @@ hid_t fid, group;
   H5Gclose(group);
 
   /* create path from object at /g1 to object at /g2 and name it g1.1 */
-  H5Glink (fid, H5G_LINK_HARD, "/g2", "/g1/g1.1");
+  H5Glink (fid, H5L_LINK_HARD, "/g2", "/g1/g1.1");
 
   /* create path from object at /g2 to object at /g1 and name it g2.1 */
-  H5Glink (fid, H5G_LINK_SOFT, "/g1", "/g2/g2.1");
+  H5Glink (fid, H5L_LINK_SOFT, "/g1", "/g2/g2.1");
 
   H5Fclose(fid);
 
@@ -1012,13 +1070,13 @@ hid_t fid, group;
 
 /*
                   /
-     |       |       |   \    \    \
-     g1     g2      g3   g4   g5    g6
-    / \      |       |    \     \    \
- g1.1 g1.2 slink2  link3 dset2 slink4 dset3
-  |    |    (g1)  (dset2)      (dset3)
- dset1 link1
-      (dset1)
+     |       |       |   \    \    \     \      \
+     g1     g2      g3   g4   g5    g6    g7     g8
+    / \      |       |    \     \    \      \      \
+ g1.1 g1.2 slink2  link3 dset2 slink4 dset3 slink5   elink
+  |    |    (g1)  (dset2)      (dset3)      (elink)  udlink
+ dset1 link1                                slink6
+      (dset1)                               (udlink)
 */
 
 static void gent_many(void) {
@@ -1043,6 +1101,7 @@ static void gent_many(void) {
     hsize_t dim[4];
     int idx[4] = {0,1,2,3};  /* normal indicies */
     const int perm[4] = {0,1,2,3};  /* the 0'th and the 3'rd indices are permuted */
+    herr_t ret;
 
   fid = H5Fcreate(FILE12, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
 
@@ -1150,11 +1209,11 @@ static void gent_many(void) {
   H5Gclose(group);
 
   group = H5Gcreate (fid, "/g1/g1.2", 0);
-  H5Glink (group, H5G_LINK_HARD, "/g1/g1.1/dset1", "link1");
+  H5Glink (group, H5L_LINK_HARD, "/g1/g1.1/dset1", "link1");
   H5Gclose(group);
 
   group = H5Gcreate (fid, "/g2", 0);
-  H5Glink (group, H5G_LINK_SOFT, "/g1", "slink2");
+  H5Glink (group, H5L_LINK_SOFT, "/g1", "slink2");
   H5Gclose(group);
 
   group = H5Gcreate (fid, "/g3", 0);
@@ -1178,7 +1237,7 @@ static void gent_many(void) {
   H5Gclose(group);
 
   group = H5Gopen(fid, "/g3");
-  H5Glink (group, H5G_LINK_HARD, "/g4/dset2", "link3");
+  H5Glink (group, H5L_LINK_HARD, "/g4/dset2", "link3");
   H5Gclose(group);
 
   group = H5Gcreate (fid, "/g5", 0);
@@ -1201,10 +1260,26 @@ static void gent_many(void) {
   H5Gclose(group);
 
   group = H5Gopen(fid, "/g5");
-  H5Glink (group, H5G_LINK_SOFT, "/g6/dset3", "slink4");
+  H5Glink (group, H5L_LINK_SOFT, "/g6/dset3", "slink4");
   H5Gclose(group);
   H5Pclose(create_plist);
 
+  group = H5Gcreate (fid, "/g7", 0);
+  H5Gclose(group);
+  group = H5Gcreate (fid, "/g8", 0);
+  H5Gclose(group);
+
+  /* Create dangling external and UD links */
+  H5Lcreate_external("somefile", "somepath", fid, "/g8/elink", H5P_DEFAULT, H5P_DEFAULT);
+  H5Lregister(UD_link_class);
+  H5Lcreate_ud(fid, "/g8/udlink", MY_LINKCLASS, NULL, 0, H5P_DEFAULT, H5P_DEFAULT);
+
+  /* Create links to external and UD links */
+  ret= H5Glink (fid, H5L_LINK_SOFT, "/g8/elink", "/g7/slink5");
+  HDassert(ret >= 0);
+  ret= H5Glink (fid, H5L_LINK_SOFT, "/g8/udlink", "/g7/slink6");
+  HDassert(ret >= 0);
+
   H5Fclose(fid);
 
 }
@@ -4927,42 +5002,48 @@ static void gent_fcontents(void)
 
  /* hard link to "dset" */
  gid1 = H5Gcreate (fid, "/g1", 0);
- H5Glink (gid1, H5G_LINK_HARD, "/dset", "dset1");
+ H5Glink (gid1, H5L_LINK_HARD, "/dset", "dset1");
  H5Gclose(gid1);
 
 
  /* hard link to "dset" */
  gid1 = H5Gcreate (fid, "/g2", 0);
- H5Glink (gid1, H5G_LINK_HARD, "/dset", "dset2");
+ H5Glink (gid1, H5L_LINK_HARD, "/dset", "dset2");
  H5Gclose(gid1);
 
 
  /* hard link to "g2" */
  gid1 = H5Gopen(fid, "/g1");
- H5Glink (gid1, H5G_LINK_HARD, "/g2", "g1.1");
+ H5Glink (gid1, H5L_LINK_HARD, "/g2", "g1.1");
  H5Gclose(gid1);
 
 
  /* hard link to "dset" */
- ret=H5Glink (fid, H5G_LINK_HARD, "/dset", "dset3");
+ ret=H5Glink (fid, H5L_LINK_HARD, "/dset", "dset3");
  assert(ret>=0);
 
 
  /* hard link to "dset" */
- ret=H5Glink (fid, H5G_LINK_HARD, "/dset", "dset4");
+ ret=H5Glink (fid, H5L_LINK_HARD, "/dset", "dset4");
  assert(ret>=0);
 
 
  /* soft link to itself */
- ret=H5Glink (fid, H5G_LINK_SOFT, "mylink", "mylink");
+ ret=H5Glink (fid, H5L_LINK_SOFT, "mylink", "mylink");
  assert(ret>=0);
 
 
  /* soft link to "dset" */
- ret=H5Glink (fid, H5G_LINK_SOFT, "/dset", "softlink");
+ ret=H5Glink (fid, H5L_LINK_SOFT, "/dset", "softlink");
  assert(ret>=0);
 
+ /* dangling external link */
+ ret=H5Lcreate_external("fname", "oname", fid, "extlink", H5P_DEFAULT, H5P_DEFAULT);
+ assert(ret>=0);
 
+ /* dangling udlink */
+ ret=H5Lcreate_ud(fid, "udlink", MY_LINKCLASS, NULL, 0, H5P_DEFAULT, H5P_DEFAULT);
+ assert(ret>=0);
 
 /*-------------------------------------------------------------------------
  * datatypes
@@ -5397,11 +5478,11 @@ static void gent_longlinks(void)
     objname[F51_MAX_NAME_LEN] = '\0';
 
     /* Create hard link to existing object */
-    assert(H5Glink2(fid, "grp1", H5G_LINK_HARD, fid, objname) >= 0);
+    assert(H5Lcreate_hard(fid, "grp1", fid, objname, H5P_DEFAULT) >= 0);
 
     /* Create soft link to existing object */
     objname[0] = 'b';
-    assert(H5Glink2(fid, "grp1", H5G_LINK_SOFT, fid, objname) >= 0);
+    assert(H5Lcreate_soft("grp1", fid, objname, H5P_DEFAULT) >= 0);
 
     /* Create group with long name in existing group */
     gid2=H5Gcreate(gid, objname, (size_t)0);
@@ -5444,7 +5525,7 @@ static int gent_ldouble(void)
  if ((tid = H5Tcopy(H5T_NATIVE_LDOUBLE))<0)
   goto error;
 
- if ((size = H5Tget_size(tid))<0)
+ if ((size = H5Tget_size(tid))==0)
   goto error;
 
  if ((did = H5Dcreate(fid, "dset", tid, sid, H5P_DEFAULT))<0)
@@ -5483,6 +5564,8 @@ int main(void)
     gent_softlink();
     gent_dataset();
     gent_hardlink();
+    gent_extlink();
+    gent_udlink();
     gent_compound_dt();
     gent_all();
     gent_loop();
diff --git a/tools/h5dump/testh5dump.sh.in b/tools/h5dump/testh5dump.sh.in
index 783634c..3f40976 100644
--- a/tools/h5dump/testh5dump.sh.in
+++ b/tools/h5dump/testh5dump.sh.in
@@ -125,10 +125,12 @@ TOOLTEST tattr-3.ddl --header -a /attr2 --attribute=/attr tattr.h5
 # test for displaying attributes in shared datatype (also in group and dataset)
 TOOLTEST tnamed_dtype_attr.ddl tnamed_dtype_attr.h5
 
-# test for displaying soft links
+# test for displaying soft links and user-defined links
 TOOLTEST tslink-1.ddl tslink.h5
+TOOLTEST tudlink-1.ddl tudlink.h5
 # test for displaying the selected link
 TOOLTEST tslink-2.ddl -l slink2 tslink.h5
+TOOLTEST tudlink-2.ddl -l udlink2 tudlink.h5
 
 # tests for hard links
 TOOLTEST thlink-1.ddl thlink.h5
diff --git a/tools/h5dump/testh5dumpxml.sh.in b/tools/h5dump/testh5dumpxml.sh.in
index 21db71a..490832e 100755
--- a/tools/h5dump/testh5dumpxml.sh.in
+++ b/tools/h5dump/testh5dumpxml.sh.in
@@ -118,6 +118,8 @@ TOOLTEST tcompound_complex.h5.xml --xml tcompound_complex.h5
 TOOLTEST tobjref.h5.xml --xml tobjref.h5
 TOOLTEST topaque.h5.xml --xml topaque.h5
 TOOLTEST tslink.h5.xml --xml tslink.h5
+TOOLTEST tudlink.h5.xml --xml tudlink.h5
+TOOLTEST textlink.h5.xml --xml textlink.h5
 TOOLTEST tstr.h5.xml --xml tstr.h5
 TOOLTEST tstr2.h5.xml --xml tstr2.h5
 TOOLTEST tref.h5.xml --xml tref.h5