Use the basename for the HDF5 files as these are relative to the container...

Use the basename for the HDF5 files as these are relative to the container file and could include directory information (we assume XMF file is written into same directory as the snapshots).

src/xmf.c

 /*******************************************************************************
  * This file is part of SWIFT.
  * Copyright (c) 2017 Matthieu Schaller (matthieu.schaller@durham.ac.uk).
+ *                    Peter W. Draper   (p.w.draper@durham.ac.uk)
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as published
@@ -21,7 +22,9 @@
 #include "../config.h"
 
 /* Some standard headers. */
+#include <libgen.h>
 #include <stdio.h>
+#include <string.h>
 
 /* This object's header. */
 #include "xmf.h"
@@ -30,6 +33,22 @@
 #include "common_io.h"
 #include "error.h"
 
+/**
+ * @brief Return the basename of an HDF5 path.
+ *
+ * Need basename as XML paths are relative to the container, and XMF file is
+ * written with the same baseName as the HDF5 snapshots.
+ *
+ * @param hdfFileName
+ * @return the basename part of hdfFileName.
+ */
+static const char *xmf_basename(const char *hdfFileName) {
+  static char buffer[FILENAME_BUFFER_SIZE];
+  strcpy(buffer, hdfFileName);
+  return basename(buffer);
+}
+
+
 /**
  * @brief Prepare the XMF file corresponding to a snapshot.
  *
@@ -154,6 +173,7 @@ void xmf_write_outputfooter(FILE* xmfFile, int output, float time) {
  */
 void xmf_write_groupheader(FILE* xmfFile, char* hdfFileName, size_t N,
                            enum part_type ptype) {
+
   fprintf(xmfFile, "\n<Grid Name=\"%s\" GridType=\"Uniform\">\n",
           part_type_names[ptype]);
   fprintf(xmfFile,
@@ -163,7 +183,7 @@ void xmf_write_groupheader(FILE* xmfFile, char* hdfFileName, size_t N,
           "<DataItem Dimensions=\"%zu 3\" NumberType=\"Double\" "
           "Precision=\"8\" "
           "Format=\"HDF\">%s:/PartType%d/Coordinates</DataItem>\n",
-          N, hdfFileName, (int)ptype);
+          N, xmf_basename(hdfFileName), (int)ptype);
   fprintf(xmfFile,
           "</Geometry>\n <!-- Done geometry for %s, start of particle fields "
           "list -->\n",
@@ -251,13 +271,13 @@ void xmf_write_line(FILE* xmfFile, const char* fileName,
     fprintf(xmfFile,
             "<DataItem Dimensions=\"%zu\" NumberType=\"%s\" "
             "Precision=\"%d\" Format=\"HDF\">%s:%s/%s</DataItem>\n",
-            N, xmf_type(type), xmf_precision(type), fileName, partTypeGroupName,
-            name);
+            N, xmf_type(type), xmf_precision(type), xmf_basename(fileName),
+            partTypeGroupName, name);
   else
     fprintf(xmfFile,
             "<DataItem Dimensions=\"%zu %d\" NumberType=\"%s\" "
             "Precision=\"%d\" Format=\"HDF\">%s:%s/%s</DataItem>\n",
-            N, dim, xmf_type(type), xmf_precision(type), fileName,
-            partTypeGroupName, name);
+            N, dim, xmf_type(type), xmf_precision(type),
+            xmf_basename(fileName), partTypeGroupName, name);
   fprintf(xmfFile, "</Attribute>\n");
 }