diff --git a/dlls/ntdll/ntdll.spec b/dlls/ntdll/ntdll.spec
index 5ac5a16ed44..36d997d1762 100644
--- a/dlls/ntdll/ntdll.spec
+++ b/dlls/ntdll/ntdll.spec
@@ -1625,7 +1625,7 @@
 @ cdecl -syscall wine_server_handle_to_fd(long long ptr ptr)
 
 # Unix interface
-@ cdecl -syscall __wine_unix_call(int64 long ptr)
+@ stdcall -syscall __wine_unix_call(int64 long ptr)
 @ cdecl __wine_set_unix_funcs(long ptr)
 @ cdecl __wine_init_unix_lib(long long ptr ptr)
 @ stdcall __wine_ctrl_routine(ptr)
diff --git a/dlls/ntdll/unix/loader.c b/dlls/ntdll/unix/loader.c
index f1a2b9f5a79..7d9635db535 100644
--- a/dlls/ntdll/unix/loader.c
+++ b/dlls/ntdll/unix/loader.c
@@ -1141,7 +1141,7 @@ static NTSTATUS CDECL init_unix_lib( void *module, DWORD reason, const void *ptr
 /***********************************************************************
  *           __wine_unix_call
  */
-NTSTATUS CDECL __wine_unix_call( unixlib_handle_t handle, unsigned int code, void *args )
+NTSTATUS WINAPI __wine_unix_call( unixlib_handle_t handle, unsigned int code, void *args )
 {
     return ((unixlib_entry_t*)(UINT_PTR)handle)[code]( args );
 }
diff --git a/include/winternl.h b/include/winternl.h
index 562a35a83a1..523e65007ed 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -4617,7 +4617,7 @@ typedef UINT64 unixlib_handle_t;
 
 /* Wine internal functions */
 extern NTSTATUS CDECL __wine_init_unix_lib( HMODULE module, DWORD reason, const void *ptr_in, void *ptr_out );
-extern NTSTATUS CDECL __wine_unix_call( unixlib_handle_t handle, unsigned int code, void *args );
+extern NTSTATUS WINAPI __wine_unix_call( unixlib_handle_t handle, unsigned int code, void *args );
 
 /* The thread information for 16-bit threads */
 /* NtCurrentTeb()->SubSystemTib points to this */