diff --git a/lib/std/c.zig b/lib/std/c.zig
index baac4fc4c031c5626bbc220b10667d580c26c700..99654f688c00d98871818cbe1039b80420bbb4c4 100644
--- a/lib/std/c.zig
+++ b/lib/std/c.zig
@@ -11882,7 +11882,7 @@ const private = struct {
     };
     extern "c" fn getrusage(who: c_int, usage: *rusage) c_int;
     extern "c" fn gettimeofday(noalias tv: ?*timeval, noalias tz: ?*timezone) c_int;
-    extern "c" fn ioctl(fd: fd_t, request: c_int, ...) c_int;
+    extern "c" fn ioctl(fd: fd_t, request: if (native_os == .dragonfly) c_ulong else c_int, ...) c_int;
     extern "c" fn msync(addr: *align(page_size) const anyopaque, len: usize, flags: c_int) c_int;
     extern "c" fn mremap(addr: ?*align(page_size) const anyopaque, old_len: usize, new_len: usize, flags: MREMAP, ...) *anyopaque;
     extern "c" fn nanosleep(rqtp: *const timespec, rmtp: ?*timespec) c_int;