diff --git a/lib/strtoofft.c b/lib/strtoofft.c
index a6f1f01f3b7521cedf66b08bcb56e2814cd4271a..1bcfb1af4fe0b6adfe220e92890fd50ecf3b3ff9 100644
--- a/lib/strtoofft.c
+++ b/lib/strtoofft.c
@@ -36,7 +36,7 @@ static int get_char(char c, int base);
  * value from the given input string and returns it.
  */
 curl_off_t
-Curl_strtoll(const char *nptr, char **endptr, int base)
+curlx_strtoll(const char *nptr, char **endptr, int base)
 {
   char *end;
   int is_negative = 0;
diff --git a/lib/strtoofft.h b/lib/strtoofft.h
index 4bb3b8fe642eef74c779614cb2c224402e76ab0f..0738bb474d125c497d539412e8f9144b091e428f 100644
--- a/lib/strtoofft.h
+++ b/lib/strtoofft.h
@@ -1,3 +1,5 @@
+#ifndef _CURL_STRTOOFFT_H
+#define _CURL_STRTOOFFT_H
 /***************************************************************************
  *                                  _   _ ____  _     
  *  Project                     ___| | | |  _ \| |    
@@ -21,8 +23,10 @@
  * $Id$
  ***************************************************************************/
 
-#ifndef _CURL_STRTOOFFT_R_H
-#define _CURL_STRTOOFFT_R_H
+/*
+ * CAUTION: this header is designed to work when included by the app-side
+ * as well as the library. Do not mix with library internals!
+ */
 
 #include "setup.h"
 #include <stddef.h>
@@ -38,7 +42,7 @@
 #if HAVE_STRTOLL
 #define strtoofft strtoll
 #else
-curl_off_t Curl_strtoll(const char *nptr, char **endptr, int base);
+curl_off_t curlx_strtoll(const char *nptr, char **endptr, int base);
 #define strtoofft Curl_strtoll
 #define NEED_CURL_STRTOLL
 #endif