1 files changed, 5 insertions, 1 deletions

diff --git a/zconf.h.cmakein b/zconf.h.cmakein
index 247ba24..9cc20bf 100644
--- a/zconf.h.cmakein
+++ b/zconf.h.cmakein
@@ -243,7 +243,11 @@
 #endif
 
 #ifdef Z_SOLO
-   typedef unsigned long z_size_t;
+#  ifdef _WIN64
+     typedef unsigned long long z_size_t;
+#  else
+     typedef unsigned long z_size_t;
+#  endif
 #else
 #  define z_longlong long long
 #  if defined(NO_SIZE_T)