diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
index d474958b4e5..6043d32279d 100644
--- a/ext/zlib/zlib.c
+++ b/ext/zlib/zlib.c
@@ -127,7 +127,7 @@ static void php_zlib_init_globals(ZLIBLS_D)
 PHP_MINIT_FUNCTION(zlib)
 {
 #ifdef ZTS
-        zlib_globals_id = ts_allocate_id(sizeof(php_zlib_globals), php_zlib_init_globals, NULL);
+        zlib_globals_id = ts_allocate_id(sizeof(php_zlib_globals), (ts_allocate_ctor) php_zlib_init_globals, NULL);
 #else
         ZLIBG(gzgetss_state)=0;
 #endif