diff options
Diffstat (limited to 'lib/libufs/cgread.3')
-rw-r--r-- | lib/libufs/cgread.3 | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/lib/libufs/cgread.3 b/lib/libufs/cgread.3 new file mode 100644 index 0000000..38edf17 --- /dev/null +++ b/lib/libufs/cgread.3 @@ -0,0 +1,106 @@ +.\" Author: Juli Mallett <jmallett@FreeBSD.org> +.\" Date: June 04, 2003 +.\" Description: +.\" Manual page for libufs functions: +.\" cgread(3) +.\" cgread1(3) +.\" cgwrite1(3) +.\" +.\" This file is in the public domain. +.\" +.\" $FreeBSD$ +.\" +.Dd June 4, 2003 +.Dt CGREAD 3 +.Os +.Sh NAME +.Nm cgread , cgread1, cgwrite1 +.Nd read/write cylinder groups of UFS disks +.Sh LIBRARY +.Lb libufs +.Sh SYNOPSIS +.In sys/param.h +.In sys/mount.h +.In ufs/ufs/ufsmount.h +.In ufs/ufs/dinode.h +.In ufs/ffs/fs.h +.In libufs.h +.Ft int +.Fn cgread "struct uufsd *disk" +.Ft int +.Fn cgread1 "struct uufsd *disk" "int c" +.Ft int +.Fn cgwrite1 "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 +.Va d_cg +field of a userland UFS disk structure. +It sets the +.Va d_lcg +field to the cylinder group number +.Fa c . +.Pp +The +.Fn cgread +function operates on sequential cylinder groups. +Calling the +.Fn cgread +function is equivalent to calling +.Fn cgread1 +with a cylinder group specifier equivalent to the value of the current +.Va d_ccg +field, and then incrementing the +.Va d_ccg +field. +.Pp +The +.Fn cgwrite1 +function stores cylinder group specified by +.Fa c +from +.Va d_cg +field of a userland UFS disk structure on disk. +.Sh 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. +.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 . +.Pp +The function +.Fn cgread1 +has semantically identical failure conditions to those of +.Fn cgread . +.Pp +The function +.Fn cgwrite1 +may fail and set +.Va errno +for any of the errors specified for the library function +.Xr bwrite 3 . +.Sh SEE ALSO +.Xr bread 3 , +.Xr bwrite 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 |