diff --git a/src/proto/crypt.pro b/src/proto/crypt.pro
index c067829..d599238 100644
--- a/src/proto/crypt.pro
+++ b/src/proto/crypt.pro
@@ -22,6 +22,7 @@
 void crypt_decode_inplace(cryptstate_T *state, char_u *buf, size_t len, int last);
 void crypt_free_key(char_u *key);
 void crypt_check_method(int method);
+void crypt_check_swapfile_curbuf(void);
 void crypt_check_current_method(void);
 char_u *crypt_get_key(int store, int twice);
 void crypt_append_msg(buf_T *buf);