diff --git a/libs/libc/stdio/Kconfig b/libs/libc/stdio/Kconfig
index bcec3917cb..3e787562d8 100644
--- a/libs/libc/stdio/Kconfig
+++ b/libs/libc/stdio/Kconfig
@@ -80,6 +80,9 @@ config LIBC_LONG_LONG
 		libraries that will be drawn into the build if long long support
 		is enabled.
 
+		NOTE:  This setting has no effect if the underlying architecture
+		cannot support long long types
+
 config LIBC_NUMBERED_ARGS
 	bool "Enable numbered arguments in printf"
 	default n
diff --git a/libs/libc/stdio/lib_libvscanf.c b/libs/libc/stdio/lib_libvscanf.c
index e9ca092b34..df805bcd18 100644
--- a/libs/libc/stdio/lib_libvscanf.c
+++ b/libs/libc/stdio/lib_libvscanf.c
@@ -1,8 +1,8 @@
 /****************************************************************************
  * libs/libc/stdio/lib_libsscanf.c
  *
- *   Copyright (C) 2007, 2008, 2011-2014, 2016, 2019 Gregory Nutt. All rights
- *     reserved.
+ *   Copyright (C) 2007, 2008, 2011-2014, 2016, 2019 Gregory Nutt. All
+ *     rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *           Johannes Schock
  *
@@ -52,6 +52,7 @@
 #include <errno.h>
 #include <debug.h>
 
+#include <nuttx/compiler.h>
 #include <nuttx/streams.h>
 
 #include "libc.h"
@@ -60,6 +61,14 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* CONFIG_LIBC_LONG_LONG is not a valid selection of the compiler does not
+ * support long long types.
+ */
+
+#ifndef CONFIG_HAVE_LONG_LONG
+#  undef CONFIG_LIBC_LONG_LONG
+#endif
+
 #define MAXLN   128
 
 #define HH_MOD -2
diff --git a/libs/libc/stdio/lib_ultoa_invert.h b/libs/libc/stdio/lib_ultoa_invert.h
index c7e89bdb8a..7f7d3fb86a 100644
--- a/libs/libc/stdio/lib_ultoa_invert.h
+++ b/libs/libc/stdio/lib_ultoa_invert.h
@@ -48,6 +48,14 @@
  * Pre-processor Definitions
  ****************************************************************************/
 
+/* CONFIG_LIBC_LONG_LONG is not a valid selection of the compiler does not
+ * support long long types.
+ */
+
+#ifndef CONFIG_HAVE_LONG_LONG
+#  undef CONFIG_LIBC_LONG_LONG
+#endif
+
 /* Next flags are to use with `base'. Unused fields are reserved. */
 
 #define XTOA_PREFIX  0x0100    /* Put prefix for octal or hex */