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Command: eopnotsupp | Section: 9 | Source: NetBSD | File: eopnotsupp.9
NULLOP(9) FreeBSD Kernel Developer's Manual NULLOP(9)
NAME
nullop - dummy functions
SYNOPSIS
#include <sys/systm.h>
int
nullop(void *v);
void
voidop(void);
int
enodev(void);
int
enxio(void);
int
enoioctl(void);
int
enosys(void);
int
eopnotsupp(void);
DESCRIPTION
The nullop() function provides a generic "null operation". It always
returns the value 0. The voidop() function takes no arguments and does
nothing.
The enodev(), enxio(), enoioctl(), enosys(), and eopnotsupp() functions
always fail, returning ENODEV, ENXIO, ENOTTY, ENOSYS, and EOPNOTSUPP,
respectively.
EXAMPLES
The following example demonstrates a case where nullop() may be useful:
uint64_t xc;
...
xc = xc_broadcast(0, (xcfunc_t)nullop, NULL, NULL);
xc_wait(xc);
FreeBSD 14.1-RELEASE-p8 July 25, 2010 FreeBSD 14.1-RELEASE-p8