---
name: "rpma_atomic_write"
section: "3"
platform: "linux"
package: "librpma-dev"
version: "1.3.0-2+b3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/rpma_atomic_write"
---

# rpma\_atomic\_write(3)

## NAME

**rpma\_atomic\_write -- initiate the atomic 8 bytes write operation**

## SYNOPSIS

```
      #include <librpma.h>
      struct rpma_conn;
      struct rpma_mr_remote;
      int rpma_atomic_write(struct rpma_conn *conn,
                      struct rpma_mr_remote *dst, size_t dst_offset,
                      const char src[8], int flags, const void *op_context);
```

## DESCRIPTION

**rpma\_atomic\_write() initiates the atomic 8 bytes write operation (transferring data from** **the local memory to the remote memory). The atomic write operation allows transferring exactly 8** **bytes of data and storing them atomically in the remote memory.**

**The attribute flags set the completion notification indicator:**

- •

  **RPMA\_F\_COMPLETION\_ON\_ERROR - generate the completion on error**

- •

  **RPMA\_F\_COMPLETION\_ALWAYS - generate the completion regardless of result of the operation.**

**op\_context is returned in the wr\_id field of the completion (struct ibv\_wc).**

## RETURN VALUE

**The rpma\_atomic\_write() function returns 0 on success or a negative error code on failure.**

## ERRORS

**rpma\_atomic\_write() can fail with the following errors:**

- •

  **RPMA\_E\_INVAL - conn, dst or src is NULL**

- •

  **RPMA\_E\_INVAL - dst\_offset is not aligned to 8 bytes**

- •

  **RPMA\_E\_INVAL - flags are not set (flags == 0)**

- •

  **RPMA\_E\_PROVIDER - [ibv\_post\_send(3)](/ibv_post_send/3.md) failed**

## SEE ALSO

**[rpma\_conn\_req\_connect(3)](/rpma_conn_req_connect/3.md), [rpma\_mr\_reg(3)](/rpma_mr_reg/3.md), [rpma\_mr\_remote\_from\_descriptor(3)](/rpma_mr_remote_from_descriptor/3.md), [librpma(7)](/librpma/7.md) and** **https://pmem.io/rpma/**