diff --git a/mysys/mf_tempfile.cc b/mysys/mf_tempfile.cc
index 7c1741541ab..aae26bf8451 100644
--- a/mysys/mf_tempfile.cc
+++ b/mysys/mf_tempfile.cc
@@ -89,7 +89,7 @@ File create_temp_file(char *to, const char *dir, const char *prefix,
 #endif
 
   DBUG_ENTER("create_temp_file");
-  DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir, prefix));
+  DBUG_PRINT("enter", ("dir: %s, prefix: %s", dir ? dir : "(null)", prefix));
 #if defined(_WIN32)
 
   /*
@@ -122,6 +122,7 @@ File create_temp_file(char *to, const char *dir, const char *prefix,
   }
 
 #else /* mkstemp() is available on all non-Windows supported platforms. */
+  if (!dir && !(dir = getenv("TMPDIR"))) dir = DEFAULT_TMPDIR;
 #ifdef O_TMPFILE
   {
     static int O_TMPFILE_works = 1;
@@ -157,7 +158,6 @@ File create_temp_file(char *to, const char *dir, const char *prefix,
                                           sizeof(prefix_buff) - 7),
                                "XXXXXX") -
                      prefix_buff);
-    if (!dir && !(dir = getenv("TMPDIR"))) dir = DEFAULT_TMPDIR;
     if (strlen(dir) + pfx_len > FN_REFLEN - 2) {
       errno = ENAMETOOLONG;
       set_my_errno(ENAMETOOLONG);