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unlink(2)
NAME
  unlink - Remove a directory entry

SYNOPSIS
  #include <unistd.h>

  int unlink(
	  const char *path );

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  unlink(): XSH4.0, XSH4.2, XSH5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  path
      Specifies the directory entry to be removed.

DESCRIPTION
  When the directory entry is a hard link, the unlink() function removes it
  and decrements the link count of the file referenced by the link. When the
  directory entry is a symbolic link, the unlink() function removes the
  symbolic link and does not affect any file or directory named by the
  contents of the symbolic link.

  When all links to a file are removed and no process has the file open or
  mapped, all resources associated with the file are reclaimed, and the file
  is no longer accessible. If one or more processes have the file open or
  mapped when the last link is removed, the link is removed before the
  unlink() function returns, but the removal of the file contents is
  postponed until all open or map references to the file are removed.

  A hard link to a directory cannot be unlinked.

  A process must have write access to the parent directory of the file to be
  unlinked with respect to all access policies.

  Upon successful completion, the unlink() function marks for update the
  st_ctime and st_mtime fields of the directory which contained the link. If
  the file's link count is not 0 (zero), the st_ctime field of the file is
  also marked for update.

  System V Compatibility

  [Tru64 UNIX]	Any attempt to unlink non-empty directories in the System V
  habitat will cause the unlink() call to fail and set errno to [ENOTEMPTY],
  even if the process has superuser privileges. This error behavior is
  provided in the System V habitat to comply with the SVID-2 specification.

RETURN VALUES
  Upon successful completion, a value of 0 (zero) is returned. If the
  unlink() function fails, a value of -1 is returned, the named file is not
  changed, and errno is set to indicate the error.

ERRORS
  If the unlink() function fails, the named file is not unlinked and errno
  may be set to one of the following values:

  [EACCES]
      One of the following conditions was encountered:

	·  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.

	·  The S_ISVTX option is set on the directory containing the file
	   referred to by the path argument and the caller is not the file
	   owner, nor is the caller the directory owner, nor does the caller
	   have appropriate privileges.

  [EBUSY]
      One of the following conditions was encountered:

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

	·  The file named by path is a named STREAM.

  [EFAULT]
      [Tru64 UNIX]  The path parameter is an invalid address.

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

  [ENAMETOOLONG]
      The length of the path parameter exceeds PATH_MAX or a pathname
      component is longer than NAME_MAX; or, pathname resolution  of a
      symbolic link produced an intermediate result whose length exceeds
      PATH_MAX.

  [ENOENT]
      The named file does not exist or the path parameter points to an empty
      string.

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

  [EPERM]
      One of the following conditions was encountered:

	·  The named file is a directory.

	·  The S_ISVTX option is set on the directory containing the file
	   referred to by the path argument and the caller is not the file
	   owner, nor is the caller the directory owner, nor does the caller
	   have appropriate privileges.

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

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

  [Tru64 UNIX]	For NFS file access, if the link() function fails, errno may
  also be set to one of the following values:

  [EISDIR]
      Indicates either that the request was for a write access to a file but
      the specified filename was actually a directory, or that the function
      was trying to rename a directory as a file.

  [ENFILE]
      Indicates either that the system file table is full, or that there are
      too many files currently open in the system.

  [ESTALE]
      Indicates a stale NFS file handle.  A client cannot delete a link
      because the server has unmounted or unexported the remote directory; or
      the directory that contains an file was either unmounted or unexported
      by the server.

SEE ALSO
  Commands: link(1), rm(1), unlink(1)

  Functions: close(2), link(2), open(2), rmdir(2)

  Standards: standards(5)

Index for Section 2

Alphabetical listing for U

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