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OpenSolaris 2009.06 - man page for unlink (opensolaris section 2)

unlink(2)				   System Calls 				unlink(2)

       unlink, unlinkat - remove directory entry

       #include <unistd.h>

       int unlink(const char *path);

       int unlinkat(int dirfd, const char *path, int flag);

       The  unlink()  function	removes a link to a file. If path names a symbolic link, unlink()
       removes the symbolic link named by path and does not affect any file or directory named by
       the  contents  of  the  symbolic  link.	Otherwise, unlink() removes the link named by the
       pathname pointed to by path and decrements the link count of the file  referenced  by  the

       The unlinkat() function also removes a link to a file. See fsattr(5). If the flag argument
       is 0, the behavior of unlinkat() is the same as unlink() except in the processing  of  its
       path  argument. If path is absolute, unlinkat() behaves the same as unlink() and the dirfd
       argument is unused. If path is relative and dirfd  has  the  value  AT_FDCWD,  defined  in
       <fcntl.h>, unlinkat() also behaves the same as unlink(). Otherwise, path is resolved rela-
       tive to the directory referenced by the dirfd argument.

       If the flag argument is set to the value AT_REMOVEDIR, defined  in  <fcntl.h>,  unlinkat()
       behaves	the  same  as rmdir(2) except in the processing of the path argument as described

       When the file's link count becomes 0 and no process has the file open, the space  occupied
       by  the	file will be freed and the file is no longer accessible. If one or more processes
       have the file open when the last link is removed, the link is removed before  unlink()  or
       unlinkat() returns, but the removal of the file contents is postponed until all references
       to the file are closed.

       If the path argument is a directory and the filesystem supports unlink() and unlinkat() on
       directories,  the  directory  is unlinked from its parent with no cleanup being performed.
       In UFS, the disconnected directory will be found the next time the filesystem  is  checked
       with fsck(1M). The unlink() and unlinkat() functions will not fail simply because a direc-
       tory is not empty. The user with appropriate privileges can orphan a  non-empty	directory
       without generating an error message.

       If  the	path  argument	is  a  directory and the filesystem does not support unlink() and
       unlink() on directories (for example, ZFS), the call will fail with errno set to EPERM.

       Upon successful completion, unlink() and unlinkat() will mark for update the st_ctime  and
       st_mtime  fields of the parent directory.  If the file's link count is not 0, the st_ctime
       field of the file will be marked for update.

       Upon successful completion, 0 is returned.  Otherwise, -1 is returned,  errno  is  set  to
       indicate the error, and the file is not unlinked.

       The unlink() and unlinkat() functions will fail if:

       EACCES	       Search  permission  is denied for a component of the path prefix, or write
		       permission is denied on the directory containing the link to be removed.

       EACCES	       The parent directory has the sticky bit set and the file is  not  writable
		       by the user, the user does not own the parent directory, the user does not
		       own the file, and the user is not a privileged user.

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

       EFAULT	       The path argument points to an illegal address.

       EILSEQ	       The path argument includes non-UTF8 characters and the file system accepts
		       only file names where all characters are part of the UTF-8 character code-

       EINTR	       A signal was caught during the execution of the unlink() function.

       ELOOP	       Too many symbolic links were encountered in translating path.

       ENAMETOOLONG    The length of the path argument exceeds PATH_MAX, or the length of a  path
		       component exceeds NAME_MAX while _POSIX_NO_TRUNC is in effect.

       ENOENT	       The named file does not exist or is a null pathname.

       ENOLINK	       The  path argument points to a remote machine and the link to that machine
		       is no longer active.

       ENOTDIR	       A component of the path prefix is not a directory or the  provided  direc-
		       tory  descriptor  for  unlinkat()  is not AT_FDCWD or does not reference a

       EPERM	       The named file is a directory and {PRIV_SYS_LINKDIR} is	not  asserted  in
		       the effective set of the calling process, or the filesystem implementation
		       does not support unlink() or unlinkat() on directories.

       EROFS	       The directory entry to be unlinked is part of a read-only file system.

       The unlink() and unlinkat() functions may fail if:

       ENAMETOOLONG    Pathname resolution of a symbolic link  produced  an  intermediate  result
		       whose length exceeds {PATH_MAX}.

       ETXTBSY	       The  entry  to be unlinked is the last directory entry to a pure procedure
		       (shared text) file that is being executed.

       Applications should use rmdir(2) to remove a directory.

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Interface Stability	     |unlink()	  is	Standard;  |
       |			     |unlinkat() is Evolving	   |
       |MT-Level		     |Async-Signal-Safe 	   |

       rm(1),  close(2),  link(2),  open(2),  rmdir(2), remove(3C), attributes(5), privileges(5),

SunOS 5.11				   18 May 2007					unlink(2)

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