RENAME(2) BSD System Calls Manual RENAME(2)

NAME
     rreennaammee - change the name of a file

SYNOPSIS
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     int
     rreennaammee(const char *old, const char *new);

DESCRIPTION
     The rreennaammee() system call causes the link named old to be renamed as new.
     If new exists, it is first removed.  Both old and new must be of the same
     type (that is, both must be either directories or non-directories) and
     must reside on the same file system.

     The rreennaammee() system call guarantees that an instance of new will always
     exist, even if the system should crash in the middle of the operation.

     If the final component of old is a symbolic link, the symbolic link is
     renamed, not the file or directory to which it points.

CCAAVVEEAATT
     The system can deadlock if a loop is present in the file system graph.
     This loop takes the form of an entry in directory `a', say `a/foo', being
     a hard link to directory `b', and an entry in directory `b', say `b/bar',
     being a hard link to directory `a'.  When such a loop exists and two sep-
     arate processes attempt to perform `rename a/foo b/bar' and `rename b/bar
     a/foo', respectively, the system may deadlock attempting to lock both
     directories for modification.

     Whether or not hard links to directories are supported is specific to the
     underlying filesystem implementation.

     It is recommended that any hard links to directories in an underlying
     filesystem should be replaced by symbolic links by the system administra-
     tor to avoid the possibility of deadlocks.

RETURN VALUES
     A 0 value is returned if the operation succeeds, otherwise rreennaammee()
     returns -1 and the global variable errno indicates the reason for the
     failure.

EERRRROORRSS
     The rreennaammee() system call will fail and neither of the argument files will
     be affected if:

     [EACCES]           A component of either path prefix denies search per-
                        mission.

     [EACCES]           The requested operation requires writing in a direc-
                        tory (e.g., new, new/.., or old/..) whose modes disal-
                        low this.

     [EDQUOT]           The directory in which the entry for the new name is
                        being placed cannot be extended because the user's
                        quota of disk blocks on the file system containing the
                        directory has been exhausted.

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

     [EINVAL]           Old is a parent directory of new, or an attempt is
                        made to rename `.' or `..'.

     [EIO]              An I/O error occurs while making or updating a direc-
                        tory entry.

     [EISDIR]           new is a directory, but old is not a directory.

     [ELOOP]            Too many symbolic links are encountered in translating
                        either pathname.  This is taken to be indicative of a
                        looping symbolic link.

     [ENAMETOOLONG]     A component of a pathname exceeds {NAMEMAX} charac-
                        ters, or an entire path name exceeds {PATHMAX} char-
                        acters.

     [ENOENT]           A component of the old path does not exist, or a path
                        prefix of new does not exist.

     [ENOSPC]           The directory in which the entry for the new name is
                        being placed cannot be extended because there is no
                        space left on the file system containing the direc-
                        tory.

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

     [ENOTDIR]          old is a directory, but new is not a directory.

     [ENOTEMPTY]        New is a directory and is not empty.

     [EPERM]            The directory containing old is marked sticky, and
                        neither the containing directory nor old are owned by
                        the effective user ID.

     [EPERM]            The new file exists, the directory containing new is
                        marked sticky, and neither the containing directory
                        nor new are owned by the effective user ID.

     [EROFS]            The requested link requires writing in a directory on
                        a read-only file system.

     [EXDEV]            The link named by new and the file named by old are on
                        different logical devices (file systems).  Note that
                        this error code will not be returned if the implemen-
                        tation permits cross-device links.

CCOONNFFOORRMMAANNCCEE
     The restriction on renaming a directory whose permissions disallow writ-
     ing is based on the fact that UFS directories contain a ".." entry.  If
     renaming a directory would move it to another parent directory, this
     entry needs to be changed.

     This restriction has been generalized to disallow renaming of any write-
     disabled directory, even when this would not require a change to the ".."
     entry.  For consistency, HFS+ directories emulate this behavior.

SEE ALSO
     open(2), symlink(7)

STANDARDS
     The rreennaammee() function conforms to IEEE Std 1003.1-1988 (``POSIX.1'').

4.2 Berkeley Distribution        June 4, 1993        4.2 Berkeley Distribution