---
name: "efadv_query_ah"
section: "3"
platform: "linux"
package: "rdma-core"
version: "65.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/efadv_query_ah"
---

# efadv\_query\_ah(3)

Query EFA specific Address Handle attributes

## NAME

efadv\_query\_ah - Query EFA specific Address Handle attributes

## SYNOPSIS

-

  ```
  #include <infiniband/efadv.h>
  int efadv_query_ah(struct ibv_ah *ibvah, struct efadv_ah_attr *attr,
             uint32_t inlen);
  ```

## DESCRIPTION

**efadv\_query\_ah()** queries device-specific Address Handle attributes.

Compatibility is handled using the comp\_mask and inlen fields.

-

  ```
  struct efadv_ah_attr {
      uint64_t comp_mask;
      uint16_t ahn;
      uint8_t reserved[6];
  };
  ```

- *inlen*

  In: Size of struct efadv\_ah\_attr.

- *comp\_mask*

  Compatibility mask.

- *ahn*

  Device’s Address Handle number.

## RETURN VALUE

**efadv\_query\_ah()** returns 0 on success, or the value of errno on failure (which indicates the failure reason).

## SEE ALSO

[**efadv**(7)](/efadv/7.md)

## NOTES

- •

  Compatibility mask (comp\_mask) is an out field and currently has no values.

## AUTHORS

Gal Pressman ⟨galpress@amazon.com⟩\\c