diff --git a/CMakeLists.txt b/CMakeLists.txt
index 10aa25c08..7464c3c68 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -448,6 +448,7 @@ CHECK_TYPE_SIZE("int"		 SIZEOF_INT)
 CHECK_TYPE_SIZE("long"		 SIZEOF_LONG)
 CHECK_TYPE_SIZE("long long"	 SIZEOF_LONG_LONG)
 CHECK_TYPE_SIZE("off_t"		 SIZEOF_OFF_T)
+CHECK_TYPE_SIZE("off64_t"        SIZEOF_OFF64_T)
 CHECK_TYPE_SIZE("short"		 SIZEOF_SHORT)
 CHECK_TYPE_SIZE("size_t"	 SIZEOF_SIZE_T)
 CHECK_TYPE_SIZE("uchar"		 SIZEOF_UCHAR)
diff --git a/cmake_config.h.in b/cmake_config.h.in
index 132ba14c3..b42314ed9 100644
--- a/cmake_config.h.in
+++ b/cmake_config.h.in
@@ -44,7 +44,7 @@
 #define CHUNK_CACHE_PREEMPTION 	${CHUNK_CACHE_PREEMPTION}
 #define MAX_DEFAULT_CACHE_SIZE	${MAX_DEFAULT_CACHE_SIZE}
 #define NCIO_MINBLOCKSIZE	${NCIO_MINBLOCKSIZE}
-#cmakedefine _FILE_OFFSET_BITS
+#cmakedefine _FILE_OFFSET_BITS ${_FILE_OFFSET_BITS}
 
 
 #define PACKAGE_VERSION "${VERSION}"
@@ -184,6 +184,7 @@
 /* The size of `off_t` as computed by sizeof. */
 #cmakedefine SIZEOF_OFF_T @SIZEOF_OFF_T@
 /* The size of `short` as computed by sizeof. */
+#cmakedefine SIZEOF_OFF64_T @SIZEOF_OFF64_T@
 #cmakedefine SIZEOF_SHORT @SIZEOF_SHORT@
 /* The size of `size_t` as computed by sizeof. */
 #cmakedefine SIZEOF_SIZE_T @SIZEOF_SIZE_T@