---
name: "cmap_fd_get"
section: "3"
platform: "linux"
package: "libcmap-dev"
version: "3.1.9-2+deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/cmap_fd_get"
---

# cmap\_fd\_get(3)

Dispatches callbacks from the CMAP service

## NAME

cmap\_fd\_get - Dispatches callbacks from the CMAP service

## SYNOPSIS

**#include \<corosync/cmap.h\>**

**cs\_error\_t** **cmap\_fd\_get (cmap\_handle\_t** *handle***, int \****fd***);**

## DESCRIPTION

The **cmap\_fd\_get** function is used to retrieve the file descriptor that may be used with the poll system call to determine when **[cmap\_dispatch(3)](/cmap_dispatch/3.md)** won't block.  The *handle* argument may not be used directly with **poll** because it is not the file descriptor, but instead an internal identifier used by the CMAP library.

## RETURN VALUE

This call returns the CS\_OK value if successful, otherwise an error is returned.

## SEE ALSO

[**cmap\_dispatch**(3)](/cmap_dispatch/3.md), [**cmap\_overview**(3)](/cmap_overview/3.md)

**CS\_ERR\_TRY\_AGAIN** Resource temporarily unavailable

**CS\_ERR\_INVALID\_PARAM** Invalid argument

**CS\_ERR\_ACCESS** Permission denied

**CS\_ERR\_LIBRARY** The connection failed

**CS\_ERR\_INTERRUPT** System call interrupted by a signal

**CS\_ERR\_NOT\_SUPPORTED** The requested protocol/functionality not supported

**CS\_ERR\_MESSAGE\_ERROR** Incorrect auth message received

**CS\_ERR\_NO\_MEMORY** Not enough memory to complete the requested task