BSD syscall#480
svc · unix #480
recvmsg_x
Apple extension that receives multiple messages in a single syscall, modeled after Linux recvmmsg.
Prototype
user_ssize_t recvmsg_x(int s, struct msghdr_x *msgp, u_int cnt, int flags);Returns: user_ssize_t
Arguments
| Name | Type | Dir | Description |
|---|---|---|---|
| s | int | - | |
| msgp | struct msghdr_x | - | |
| cnt | u_int | - | |
| flags | int | - |
Version history
| XNU tag | macOS | # |
|---|---|---|
| xnu-2782.40.9 | macOS 10.10 Yosemite | 480 |
| xnu-3247.1.106 | macOS 10.11 El Capitan | 480 |
| xnu-3789.1.32 | macOS 10.12 Sierra | 480 |
| xnu-4570.1.46 | macOS 10.13 High Sierra | 480 |
| xnu-4903.221.2 | macOS 10.14 Mojave | 480 |
| xnu-6153.11.26 | macOS 10.15 Catalina | 480 |
| xnu-7195.50.7.100.1 | macOS 11.0 Big Sur | 480 |
| xnu-8019.41.5 | macOS 12.0 Monterey | 480 |
| xnu-8792.41.9 | macOS 13.0 Ventura | 480 |
| xnu-10002.1.13 | macOS 14.0 Sonoma | 480 |
| xnu-11215.1.10 | macOS 15.0 Sequoia | 480 |
| xnu-11417.101.15 | macOS 15.4 Sequoia | 480 |
| xnu-12377.1.9 | macOS 26.0 Tahoe | 480 |
| xnu-10002.41.9 | — | 480 |
| xnu-10002.61.3 | — | 480 |
| xnu-10002.81.5 | — | 480 |
| xnu-10063.101.15 | — | 480 |
| xnu-10063.121.3 | — | 480 |
| xnu-10063.141.1 | — | 480 |
| xnu-11215.41.3 | — | 480 |
| xnu-11215.61.5 | — | 480 |
| xnu-11215.81.4 | — | 480 |
| xnu-11417.121.6 | — | 480 |
| xnu-11417.140.69 | — | 480 |
| xnu-12377.101.15 | — | 480 |
| xnu-12377.41.6 | — | 480 |
| xnu-12377.61.12 | — | 480 |
| xnu-12377.81.4 | — | 480 |
| xnu-2782.1.97 | — | 480 |
| xnu-2782.10.72 | — | 480 |
| xnu-2782.20.48 | — | 480 |
| xnu-2782.30.5 | — | 480 |
| xnu-3247.10.11 | — | 480 |
| xnu-3248.20.55 | — | 480 |
| xnu-3248.30.4 | — | 480 |
| xnu-3248.40.184 | — | 480 |
| xnu-3248.50.21 | — | 480 |
| xnu-3248.60.10 | — | 480 |
| xnu-3789.21.4 | — | 480 |
| xnu-3789.31.2 | — | 480 |
| xnu-3789.41.3 | — | 480 |
| xnu-3789.51.2 | — | 480 |
| xnu-3789.60.24 | — | 480 |
| xnu-3789.70.16 | — | 480 |
| xnu-4570.20.62 | — | 480 |
| xnu-4570.31.3 | — | 480 |
| xnu-4570.41.2 | — | 480 |
| xnu-4570.51.1 | — | 480 |
| xnu-4570.61.1 | — | 480 |
| xnu-4570.71.2 | — | 480 |
| xnu-4903.231.4 | — | 480 |
| xnu-4903.241.1 | — | 480 |
| xnu-4903.270.47 | — | 480 |
| xnu-6153.101.6 | — | 480 |
| xnu-6153.121.1 | — | 480 |
| xnu-6153.141.1 | — | 480 |
| xnu-6153.41.3 | — | 480 |
| xnu-6153.61.1 | — | 480 |
| xnu-6153.81.5 | — | 480 |
| xnu-7195.101.1 | — | 480 |
| xnu-7195.121.3 | — | 480 |
| xnu-7195.141.2 | — | 480 |
| xnu-7195.60.75 | — | 480 |
| xnu-7195.81.3 | — | 480 |
| xnu-8019.61.5 | — | 480 |
| xnu-8019.80.24 | — | 480 |
| xnu-8020.101.4 | — | 480 |
| xnu-8020.121.3 | — | 480 |
| xnu-8020.140.41 | — | 480 |
| xnu-8792.61.2 | — | 480 |
| xnu-8792.81.2 | — | 480 |
| xnu-8796.101.5 | — | 480 |
| xnu-8796.121.2 | — | 480 |
| xnu-8796.141.3 | — | 480 |
Notes
Defined in <sys/msg_x.h>, recvmsg_x takes an array of struct msghdr_x and a count, returning the number of messages actually delivered. It is the Skywalk-friendly batch path used by high-throughput QUIC and WebRTC code in Apple's Network.framework. Each msghdr_x carries its own iov, cmsg, and per-message MSG_TRUNC flag — short delivery on one slot does not abort the batch.
Detection
Not exposed by ES. Detection mirrors recvmsg: NEFilterDataProvider sees the data, and SystemExtensions in DriverKit can attach to the same Skywalk nexus to mirror packets.
Related APIs
recvmsgsendmsg_x__channel_sync__channel_open