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

# umad\_open\_port(3)

open InfiniBand device port for umad access

## NAME

umad\_open\_port - open InfiniBand device port for umad access

## SYNOPSIS

```
#include <infiniband/umad.h>

int umad_open_port(char *ca_name, int portnum);
```

## DESCRIPTION

**umad\_open\_port()** opens the port *portnum* of the IB device *ca\_name* for umad access. The port is selected by the library if not all parameters are provided (see **umad\_get\_port()** for details).

## RETURN VALUE

**umad\_open\_port()** returns 0 or an unique positive value of umad device descriptor on success, and a negative value on error as follows:\
  \-EOPNOTSUPP ABI version doesn't match\
  \-ENODEV     IB device can't be resolved\
  \-EINVAL     port is not valid (bad *portnum* or no umad device)\
  \-EIO        umad device for this port can't be opened

## SEE ALSO

[**umad\_close\_port**(3)](/umad_close_port/3.md), [**umad\_get\_cas\_names**(3)](/umad_get_cas_names/3.md), [**umad\_get\_port**(3)](/umad_get_port/3.md)

## AUTHOR

- Hal Rosenstock \<halr@voltaire.com\>