diff --git a/lib/std/os/windows.zig b/lib/std/os/windows.zig
index c20457943b741a154c9a3ce5b90b03b7b9fcaf05..f6d148a3171cf5603e5b321a0b472e9d0dd3bec2 100644
--- a/lib/std/os/windows.zig
+++ b/lib/std/os/windows.zig
@@ -3695,4 +3695,4 @@ pub const CTRL_CLOSE_EVENT: DWORD = 2;
 pub const CTRL_LOGOFF_EVENT: DWORD = 5;
 pub const CTRL_SHUTDOWN_EVENT: DWORD = 6;
 
-pub const HANDLER_ROUTINE = std.meta.FnPtr(fn (dwCtrlType: DWORD) callconv(.C) BOOL);
+pub const HANDLER_ROUTINE = std.meta.FnPtr(fn (dwCtrlType: DWORD) callconv(WINAPI) BOOL);