Date: June 04, 2003
Description:
Manual page for libufs functions:
cgread(3)
cgread1(3)
$FreeBSD: head/lib/libufs/cgread.3 116087 2003-06-09 09:59:11Z jmallett $
.Dd June 04, 2003 .Dt CGREAD 3 .Os .Sh NAME .Nm cgread , cgread1 .Nd read cylinder groups of UFS disks .Sh LIBRARY .Lb libufs .Sh SYNOPSIS n sys/types.h n sys/param.h n sys/mount.h n ufs/ufs/ufsmount.h n ufs/ufs/dinode.h n ufs/ffs/fs.h n libufs.h .Ft int .Fn cgread "struct uufsd *disk" .Ft int .Fn cgread1 "struct uufsd *disk" "int c" .Sh DESCRIPTION The .Fn cgread and .Fn cgread1 functions provide cylinder group reads for .Xr libufs 3 consumers. The .Fn cgread1 function reads from one cylinder group, specified by .Fa c into the .Fa d_cg field of a userland UFS disk structure. It sets the .Fa d_lcg field to the cylinger group number .Fa c .
p The .Fn cgread function operates on sequential cylinder groups. Calling the .Fn cgread function is equivalent to calling .Nm cgread1 with a cylinder group specifier equivalent to the value of the current .Fa d_ccg field, and then incrementing the .Fa d_ccg field.
p Both functions return 0 if there are no more cylinder groups to read, 1 if there are more cylinder groups, and -1 on error. .Sh ERRORS The function .Fn cgread may fail and set .Va errno for any of the errors specified for the library function .Xr bread 3 .
p The function .Fn cgread1 has semantically identical failure conditions to those of .Fn cgread . .Sh SEE ALSO .Xr bread 3 , .Xr libufs 3 .Sh HISTORY These functions first appeared as part of .Xr libufs 3 in .Fx 5.1 . .Sh AUTHORS .An Juli Mallett Aq jmallett@FreeBSD.org