cgread(3)

NAME

cgread, cgread1 - read cylinder groups of UFS disks

LIBRARY

library ``libufs''

SYNOPSIS

#include <sys/param.h>
#include <sys/mount.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>
#include <libufs.h>
int
cgread(struct uufsd *disk);
int
cgread1(struct uufsd *disk, int c);

DESCRIPTION

The cgread() and cgread1() functions provide cylinder group

reads for
libufs(3) consumers. The cgread1() function reads from one

cylinder
group, specified by c into the d_cg field of a userland UFS

disk structure. It sets the d_lcg field to the cylinder group number

c.

The cgread() function operates on sequential cylinder

groups. Calling
the cgread() function is equivalent to calling cgread1()

with a cylinder
group specifier equivalent to the value of the current d_ccg

field, and
then incrementing the d_ccg field.

RETURN VALUES

Both functions return 0 if there are no more cylinder groups

to read, 1
if there are more cylinder groups, and -1 on error.

ERRORS

The function cgread() may fail and set errno for any of the

errors specified for the library function bread(3).

The function cgread1() has semantically identical failure

conditions to
those of cgread().

SEE ALSO

bread(3), libufs(3)

HISTORY

These functions first appeared as part of libufs(3) in

FreeBSD 5.1.

AUTHORS

Juli Mallett <jmallett@FreeBSD.org>

BSD June 4, 2003

BSD