1.\" Author: Juli Mallett <jmallett@FreeBSD.org> 2.\" Date: June 04, 2003 3.\" Description: 4.\" Manual page for libufs functions: 5.\" cgread(3) 6.\" cgread1(3) 7.\" 8.\" This file is in the public domain. 9.\" 10.\" $FreeBSD$ 11.\" 12.Dd June 4, 2003 13.Dt CGREAD 3 14.Os 15.Sh NAME 16.Nm cgread , cgread1 17.Nd read cylinder groups of UFS disks 18.Sh LIBRARY 19.Lb libufs 20.Sh SYNOPSIS 21.In sys/param.h 22.In sys/mount.h 23.In ufs/ufs/ufsmount.h 24.In ufs/ufs/dinode.h 25.In ufs/ffs/fs.h 26.In libufs.h 27.Ft int 28.Fn cgread "struct uufsd *disk" 29.Ft int 30.Fn cgread1 "struct uufsd *disk" "int c" 31.Sh DESCRIPTION 32The 33.Fn cgread 34and 35.Fn cgread1 36functions provide cylinder group reads for 37.Xr libufs 3 38consumers. 39The 40.Fn cgread1 41function reads from one cylinder group, specified by 42.Fa c 43into the 44.Va d_cg 45field of a userland UFS disk structure. 46It sets the 47.Va d_lcg 48field to the cylinder group number 49.Fa c . 50.Pp 51The 52.Fn cgread 53function operates on sequential cylinder groups. 54Calling the 55.Fn cgread 56function is equivalent to calling 57.Fn cgread1 58with a cylinder group specifier equivalent to the value of the current 59.Va d_ccg 60field, and then incrementing the 61.Va d_ccg 62field. 63.Sh RETURN VALUES 64Both functions return 0 if there are no more cylinder groups to read, 651 if there are more cylinder groups, and \-1 on error. 66.Sh ERRORS 67The function 68.Fn cgread 69may fail and set 70.Va errno 71for any of the errors specified for the library function 72.Xr bread 3 . 73.Pp 74The function 75.Fn cgread1 76has semantically identical failure conditions to those of 77.Fn cgread . 78.Sh SEE ALSO 79.Xr bread 3 , 80.Xr libufs 3 81.Sh HISTORY 82These functions first appeared as part of 83.Xr libufs 3 84in 85.Fx 5.1 . 86.Sh AUTHORS 87.An Juli Mallett Aq jmallett@FreeBSD.org 88