ultrix man page for unlink

unlink(2)							System Calls Manual							 unlink(2)

Name
       unlink - remove directory entry

Syntax
       unlink(path)
       char *path;

Description
       The  system  call  removes the entry for the file path from its directory.  If this entry was the last link to the file, and no process has
       the file open, then all resources associated with the file are reclaimed.  If, however, the file  was  open  in	any  process,  the  actual
       resource reclamation is delayed until it is closed, even though the directory entry has disappeared.

Return Values
       Upon successful completion, a value of 0 is returned.  Otherwise, a value of -1 is returned, and errno is set to indicate the error.

Diagnostics
       The system call succeeds unless:

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

       [ENOENT]       The named file does not exist or path points to an empty string and the environment defined is POSIX or SYSTEM_FIVE.

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

       [EACCES]       Write permission is denied on the directory containing the link to be removed.

       [EBUSY]	      The entry to be unlinked is the mount point for a mounted file system.

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

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

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

       [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire pathname exceeded 1023 characters.

       [EPERM]	      The named file is a directory and the effective user ID of the process is not the superuser.

       [EPERM]	      The named file is a directory and the environment is defined is POSIX.

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

       [EIO]	      An I/O error occurred while deleting the directory entry or deallocating the inode.

       [ETIMEDOUT]    A connect request or remote file operation failed, because the connected party did not properly respond after  a	period	of
		      time that is dependent on the communications protocol.

       [ETXTBSY]      The named file is the last link to a shared text executable and the environment defined is POSIX or SYSTEM_FIVE.

Environment
       Differs from the System V definition in that ELOOP is a possible error condition.

See Also
       close(2), link(2), rmdir(2)

																	 unlink(2)