diff --git a/crates/punktfunk-core/cbindgen.toml b/crates/punktfunk-core/cbindgen.toml
index df7aa21..4bfbb53 100644
--- a/crates/punktfunk-core/cbindgen.toml
+++ b/crates/punktfunk-core/cbindgen.toml
@@ -12,6 +12,12 @@ documentation_style = "c99"
 [parse]
 parse_deps = false
 
+[export]
+# Internal Apple-only FFI (transport/udp.rs `recvmsg_x` batched recv + its `MsghdrX`) — NOT part of
+# the C ABI. cbindgen otherwise sweeps the foreign import and its #[repr(C)] struct into the header,
+# where socklen_t/ssize_t/iovec are undefined and the C harness fails to compile.
+exclude = ["MsghdrX", "recvmsg_x"]
+
 [export.rename]
 "InputEvent" = "PunktfunkInputEvent"
 "InputKind" = "PunktfunkInputKind"
diff --git a/include/punktfunk_core.h b/include/punktfunk_core.h
index 82d82db..cef501e 100644
--- a/include/punktfunk_core.h
+++ b/include/punktfunk_core.h
@@ -470,18 +470,6 @@ typedef struct {
     float loss_pct;
 } PunktfunkProbeResult;
 
-// `struct msghdr_x` from Darwin `<sys/socket.h>` (the batched-I/O variant — not in the `libc` crate).
-typedef struct {
-    void *msg_name;
-    socklen_t msg_namelen;
-    iovec *msg_iov;
-    int msg_iovlen;
-    void *msg_control;
-    socklen_t msg_controllen;
-    int msg_flags;
-    size_t msg_datalen;
-} MsghdrX;
-
 #ifdef __cplusplus
 extern "C" {
 #endif // __cplusplus
@@ -899,10 +887,6 @@ PunktfunkStatus punktfunk_connection_probe_result(const PunktfunkConnection *c,
 void punktfunk_connection_close(PunktfunkConnection *c);
 #endif
 
-// Darwin batched receive: up to `cnt` datagrams in one syscall; returns the count received and
-// sets each `msg_datalen` to its byte length. Present in libSystem on all macOS/iOS.
-extern ssize_t recvmsg_x(int s, MsghdrX *msgp, unsigned int cnt, int flags);
-
 #ifdef __cplusplus
 }  // extern "C"
 #endif  // __cplusplus