io\_uring\_recvmsg\_out(3) liburing Manual io\_uring\_recvmsg\_out(3)

# [NAME](#NAME)

io\_uring\_recvmsg\_out - access data from multishot recvmsg

# [SYNOPSIS](#SYNOPSIS)

```
#include <liburing.h>
```

```
struct io_uring_recvmsg_out *io_uring_recvmsg_validate(void *buf,
                                                       int buf_len,
                                                       struct msghdr *msgh);
```

```
void *io_uring_recvmsg_name(struct io_uring_recvmsg_out *o);
```

```
struct cmsghdr *io_uring_recvmsg_cmsg_firsthdr(struct io_uring_recvmsg_out *o,
                                               struct msghdr *msgh);
struct cmsghdr *io_uring_recvmsg_cmsg_nexthdr(struct io_uring_recvmsg_out *o,
                                              struct msghdr *msgh,
                                              struct cmsghdr *cmsg);
```

```
void *io_uring_recvmsg_payload(struct io_uring_recvmsg_out *o,
                               struct msghdr *msgh);
unsigned int io_uring_recvmsg_payload_length(struct io_uring_recvmsg_out *o,
                                             int buf_len,
                                             struct msghdr *msgh);
```

```

```

# [DESCRIPTION](#DESCRIPTION)

These functions are used to access data in the payload delivered by [**io\_uring\_prep\_recvmsg\_multishot**(3)](/man/os/liburing/io_uring_prep_recvmsg_multishot.3).

*msgh* should point to the *struct msghdr* submitted with the request.

[**io\_uring\_recvmsg\_validate**(3)](/man/os/liburing/io_uring_recvmsg_validate.3) will validate a buffer delivered by [**io\_uring\_prep\_recvmsg\_multishot**(3)](/man/os/liburing/io_uring_prep_recvmsg_multishot.3) and extract the *io\_uring\_recvmsg\_out* if it is valid, returning a pointer to it or else NULL.

The structure is defined as follows:

```
struct io_uring_recvmsg_out {


        __u32 namelen;    /* Name byte count as would have been populated


                           * by recvmsg(2) */


        __u32 controllen; /* Control byte count */


        __u32 payloadlen; /* Payload byte count as would have been returned


                           * by recvmsg(2) */


        __u32 flags;      /* Flags result as would have been populated


                           * by recvmsg(2) */
};
```

- ```
  io_uring_recvmsg_name(3)
  returns a pointer to the name in the buffer.
  ```
- ```
  io_uring_recvmsg_cmsg_firsthdr(3)
  returns a pointer to the first cmsg in the buffer, or NULL.
  ```
- ```
  io_uring_recvmsg_cmsg_nexthdr(3)
  returns a pointer to the next cmsg in the buffer, or NULL.
  ```
- ```
  io_uring_recvmsg_payload(3)
  returns a pointer to the payload in the buffer.
  ```
- ```
  io_uring_recvmsg_payload_length(3)
  Calculates the usable payload length in bytes.
      
  ```

# [SEE ALSO](#SEE_ALSO)

[**io\_uring\_prep\_recvmsg\_multishot**(3)](/man/os/liburing/io_uring_prep_recvmsg_multishot.3)

July 26, 2022 liburing-2.2

---

Document: io_uring_recvmsg_payload_length(3) from liburing 2.15-r4 (Chainguard OS)
Source: https://github.com/axboe/liburing.git