lstopo: show a message about the export filename and format

Only shown if exporting to a file, that file is not stdout,
stdout is a terminal, and the output format is not window.

Signed-off-by: Brice Goglin <[email protected]>
(cherry picked from commit 096c89d)

Author: bgoglin

utils/lstopo/lstopo.c

@@ -1795,6 +1795,15 @@ main (int argc, char *argv[])
             filename);
   }
 
+#ifdef HAVE_ISATTY
+  /* if exporting to a file (which is not stdout, rewritten as "-" above),
+   * and stdout is a terminal,
+   * show a message about the export filename and format.
+   */
+  if (filename && strcmp(filename, "-") && output_format != LSTOPO_OUTPUT_WINDOW && isatty(STDOUT_FILENO))
+    printf("Exporting format `%s' to file `%s'\n", output_format_name(output_format), filename);
+#endif
+
   if (output_format != LSTOPO_OUTPUT_XML) {
     /* there might be some xml-imported userdata in objects, add lstopo-specific userdata in front of them */
     lstopo_populate_userdata(hwloc_get_root_obj(topology));