.\"	$NetBSD: chflags.2,v 1.6 1995/02/27 12:32:03 cgd Exp $
.\"
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.\"	@(#)chflags.2	8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt CHFLAGS 2
.Os
.Sh NAME
.Nm chflags ,
.Nm fchflags
.Nd set file flags
.Sh SYNOPSIS
.Fd #include <sys/stat.h>
.Fd #include <unistd.h>
.Ft int
.Fn chflags "const char *path"  "u_int flags"
.Ft int
.Fn fchflags "int fd" "u_int flags"
.Sh DESCRIPTION
The file whose name
is given by
.Fa path
or referenced by the descriptor
.Fa fd
has its flags changed to
.Fa flags .
.Pp
The flags specified are formed by
.Em or Ns 'ing
the following values
.Pp
.Bl -tag -width "SF_IMMUTABLEX" -compact -offset indent
.It UF_NODUMP
Do not dump the file.
.It UF_IMMUTABLE
The file may not be changed.
.It UF_APPEND
The file may only be appended to.
.It UF_OPAQUE
The directory is opaque when viewed through a union stack.
.It UF_HIDDEN
The file or directory is not intended to be displayed to the user.
.It SF_ARCHIVED
The file has been archived.
.It SF_IMMUTABLE
The file may not be changed.
.It SF_APPEND
The file may only be appended to.
.It SF_DATALESS 
The file is a dataless placeholder.
The system will attempt to materialize it when accessed according to the dataless file materialization policy of the accessing thread or process.
See
.Xr getiopolicy_np 3 .
.El
.Pp
The
.Dq UF_IMMUTABLE ,
.Dq UF_APPEND ,
.Dq UF_OPAQUE ,
and
.Dq UF_HIDDEN
flags may be set or unset by either the owner of a file or the super-user.
.Pp
The
.Dq SF_ARCHIVED ,
.Dq SF_IMMUTABLE
and
.Dq SF_APPEND
flags may only be set or unset by the super-user.
.Pp
The
.Dq SF_DATALESS
flag is an internal flag and may not be set from user space.
.Sh RETURN VALUES
Upon successful completion, a value of 0 is returned.
Otherwise, -1 is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn chflags
will fail if:
.Bl -tag -width Er
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded 
.Dv {NAME_MAX}
characters, or an entire path name exceeded 
.Dv {PATH_MAX}
characters.
.It Bq Er ENOENT
The named file does not exist.
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er EPERM
The effective user ID does not match the owner of the file and
the effective user ID is not the super-user.
.It Bq Er EROFS
The named file resides on a read-only file system.
.It Bq Er EFAULT
.Fa Path
points outside the process's allocated address space.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er ENOTSUP
The operation isn't supported by the filesystem.
.El
.Pp
.Fn fchflags
will fail if:
.Bl -tag -width Er
.It Bq Er EBADF
The descriptor is not valid.
.It Bq Er EINVAL
.Fa fd
refers to a socket, not to a file.
.It Bq Er EPERM
The effective user ID does not match the owner of the file and
the effective user ID is not the super-user.
.It Bq Er EROFS
The file resides on a read-only file system.
.It Bq Er EIO
An
.Tn I/O
error occurred while reading from or writing to the file system.
.It Bq Er ENOTSUP
The operation isn't supported by the filesystem.
.El
.Sh SEE ALSO
.Xr chflags 1 ,
.Xr fflagstostr 3 ,
.Xr lchflags 3 ,
.Xr strtofflags 3 ,
.Xr launchd 8
.Sh HISTORY
The
.Fn chflags
and
.Nm fchflags
functions first appeared in 4.4BSD.