diff --git a/src/c/file.d b/src/c/file.d
index 4d28b1e9a..1f8cad495 100755
--- a/src/c/file.d
+++ b/src/c/file.d
@@ -5328,7 +5328,9 @@ flisten(cl_object stream, FILE *fp)
   {
     /* regular file */
     ecl_off_t old_pos = ecl_ftello(fp), end_pos;
-    unlikely_if (ecl_fseeko(fp, 0, SEEK_END) != 0)
+    unlikely_if (old_pos == -1
+                 ||
+                 ecl_fseeko(fp, 0, SEEK_END) != 0)
       file_libc_error(@[file-error], stream,
                       "Unable to check file position", 0);
     end_pos = ecl_ftello(fp);
diff --git a/src/c/unixsys.d b/src/c/unixsys.d
index 78f8c883c..f034018bd 100644
--- a/src/c/unixsys.d
+++ b/src/c/unixsys.d
@@ -533,7 +533,7 @@ si_spawn_subprocess(cl_object command, cl_object argv, cl_object environ,
   if (Null(pid)) {
     if (parent_write) close(parent_write);
     if (parent_read) close(parent_read);
-    if (parent_error) close(parent_error);
+    if (parent_error >= 0) close(parent_error);
     parent_write = 0;
     parent_read = 0;
     parent_error = 0;