---
name: "nfsclnt"
section: "2"
platform: "macos"
package: "xnu"
version: "12377.121.6"
release: "macOS 26.5"
platforms: ["macos"]
url: "https://new.carta.tech/nfsclnt"
---

# nfsclnt(2)

NFS client services

## NAME

**nfsclnt** – NFS client services

## SYNOPSIS

**#include \<unistd.h\>**

**#include \<nfs/nfs.h\>**

*int*\

**nfsclnt**(*unsigned long request*, *void \*argstructp*);

## DESCRIPTION

The **nfsclnt**() function is used by the NFS client daemons to pass information into and out of the kernel. The *request* argument consists of several bits that show what action is to be taken once in the kernel and the *argstructp* points to any corresponding data that the action may require.

[rpc.lockd(8)](/rpc.lockd/8.md) calls **nfsclnt**() with the flag NFSCLNT\_LOCKDANS and a pointer to a

```
struct lockd_ans {
	int		la_version;		/* lockd_ans version */
	int		la_errno;		/* return status */
	u_int64_t	la_xid;			/* unique message transaction ID */
	int		la_flags;		/* answer flags */
	pid_t		la_pid;			/* pid of lock requester/owner */
	off_t		la_start;		/* lock starting offset */
	off_t		la_len;			/* lock length */
	int 		la_fh_len;		/* The file handle length. */
	u_int8_t	la_fh[NFSV3_MAX_FH_SIZE];/* The file handle. */
};
```

to pass the response to an NFS file locking request back into the kernel.

## RETURN VALUES

Upon successful completion, a value of 0 is returned.  Otherwise, -1 is returned and the global variable *errno* is set to specify the error.

## ERRORS

- \[EPERM\]

  The caller is not the super-user.

- \[EINVAL\]

  The action specified by the *flags* argument was not valid.

- \[EFAULT\]

  *argstructp* points to an invalid address.

- \[EPIPE\]

  The response doesn't match any currently-outstanding lock request.

- \[ENOSYS\]

  *nfsclnt* character device was not found.

## SEE ALSO

[rpc.lockd(8)](/rpc.lockd/8.md)

## BUGS

The **nfsclnt** system call is designed specifically for the NFS client daemons and as such is specific to their requirements.  Several fields of the argument structures are assumed to be valid, such that **nfsclnt** must be used with extreme care.