NAME

     chflags, lchflags, fchflags — set file flags

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <sys/stat.h>
     #include <unistd.h>

     int
     chflags(const char *path, u_long flags);

     int
     lchflags(const char *path, int 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 lchflags() system call is like chflags() except in the case where the named file is a
     symbolic link, in which case lchflags() will change the flags of the link itself, rather
     than the file it points to.

     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_NOUNLINK   The file may not be renamed or deleted.
           UF_OPAQUE     The directory is opaque when viewed through a union stack.
           SF_ARCHIVED   The file may be archived.
           SF_IMMUTABLE  The file may not be changed.
           SF_APPEND     The file may only be appended to.
           SF_NOUNLINK   The file may not be renamed or deleted.
           SF_SNAPSHOT   The file is a snapshot file.

     If one of SF_IMMUTABLE, SF_APPEND, or SF_NOUNLINK is set a non-super-user cannot change any
     flags and even the super-user can change flags only if securelevel is greater than 0.  (See
     init(8) for details.)

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

     The SF_IMMUTABLE, SF_APPEND, SF_NOUNLINK, and SF_ARCHIVED flags may only be set or unset by
     the super-user.  Attempts to set these flags by non-super-users are rejected, attempts by
     non-superusers to clear flags that are already unset 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.)

     The SF_SNAPSHOT flag is maintained by the system and cannot be changed by any user.

RETURN VALUES

     Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and
     the global variable errno is set to indicate the error.

ERRORS

     The chflags() system call will fail if:

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

     [ENAMETOOLONG]     A component of a pathname exceeded 255 characters, or an entire path name
                        exceeded 1023 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]            One of SF_IMMUTABLE, SF_APPEND, or SF_NOUNLINK is set and the user is
                        either not the super-user or securelevel is greater than 0.

     [EPERM]            A non-super-user tries to set one of SF_ARCHIVED, SF_IMMUTABLE,
                        SF_APPEND, or SF_NOUNLINK.

     [EPERM]            User tries to set or remove the SF_SNAPSHOT flag.

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

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

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

     [EOPNOTSUPP]       The underlying file system does not support file flags.

     The fchflags() system call will fail if:

     [EBADF]            The descriptor is not valid.

     [EINVAL]           The fd argument 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]            One of SF_IMMUTABLE, SF_APPEND, or SF_NOUNLINK is set and the user is
                        either not the super-user or securelevel is greater than 0.

     [EPERM]            A non-super-user tries to set one of SF_ARCHIVED, SF_IMMUTABLE,
                        SF_APPEND, or SF_NOUNLINK.

     [EPERM]            User tries to set or remove the SF_SNAPSHOT flag.

     [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.

     [EOPNOTSUPP]       The underlying file system does not support file flags.

SEE ALSO

     chflags(1), fflagstostr(3), strtofflags(3), init(8), mount_unionfs(8)

HISTORY

     The chflags() and fchflags() system calls first appeared in 4.4BSD.