CHFLAGS(2)

NAME
chflags, fchflags - set file flags

SYNOPSIS
#include <sys/stat.h>
#include <unistd.h>
int
chflags(const char *path, u_long flags);
int
fchflags(int fd, u_long flags);

DESCRIPTION
The file whose name is given by path or referenced by the descriptor fd has its flags changed to flags.

The flags specified are formed by or'ing the following values:

UF_NODUMP
    Do not dump the file.
UF_IMMUTABLE
    The file may not be changed.
UF_APPEND
    The file may only be appended to.
UF_OPAQUE
    The file (if a directory) is opaque for union mounts.
SF_ARCHIVED
    The file is archived.
SF_IMMUTABLE
    The file may not be changed.
SF_APPEND
    The file may only be appended to.

The UF_NODUMP, UF_IMMUTABLE, UF_APPEND, and UF_OPAQUE flags may be set or unset by either the owner of a file or the super-user.

The SF_ARCHIVED, SF_IMMUTABLE, and SF_APPEND flags may only be set or unset by the super-user. Attempts by the non-super-user to set the super-user only flags are silently ignored. These flags may be set at any time, but normally may only be unset when the system is in single-user mode. (See init(8) for details.)

RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
chflags() will fail if:

[ENOTDIR]
    A component of the path prefix is not a directory.

[ENAMETOOLONG]
    A component of a pathname exceeded {NAME_MAX} characters, or an entire path name exceeded {PATH_MAX} characters.

[ENOENT]
    The named file does not exist.

[EACCES]
    Search permission is denied for a component of the path prefix.

[ELOOP]
    Too many symbolic links were encountered in translating the pathname.

[EPERM]
    The effective user ID does not match the owner of the file and the effective user ID is not the super-user.

[EPERM]
    The effective user ID is not the super-user and one or more of the super-user-only flags for the named file would be changed.

[EOPNOTSUPP]
    The named file resides on a file system that does not support file flags.

[EROFS]
    The named file resides on a read-only file system.

[EFAULT]
    path points outside the process's allocated address space.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

fchflags() will fail if:

[EBADF]
    The descriptor is not valid.

[EINVAL]
    fd refers to a socket, not to a file.

[EPERM]
    The effective user ID does not match the owner of the file and the effective user ID is not the super-user.

[EPERM]
    The effective user ID is not the super-user and one or more of the super-user-only flags for the file would be changed.

[EOPNOTSUPP]
    The file resides on a file system that does not support file flags.

[EROFS]
    The file resides on a read-only file system.

[EIO]
    An I/O error occurred while reading from or writing to the file system.

SEE ALSO
chflags(1), init(8), mount_union(8)

HISTORY
The chflags() and fchflags() functions first appeared in 4.4BSD.