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unlink(2)

unlink(2)                        System Calls                        unlink(2)



NAME
       unlink, unlinkat - remove directory entry

SYNOPSIS
       #include <unistd.h>

       int unlink(const char *path);


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

DESCRIPTION
       The  unlink()  function  removes a link to a file. If path names a sym‐
       bolic 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 link.


       The unlinkat() function also removes a link to a file.  See  fsattr(7).
       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 argu‐
       ment 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 relative 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  pro‐
       cessing of the path argument as described above.


       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(8). The unlink() and unlinkat() functions  will  not  fail  simply
       because  a directory 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, 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.

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

ERRORS
       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, or a previously unlinked NFS file
                       waiting for references to be released.


       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 charac‐
                       ters are part of the UTF-8 character codeset.


       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 directory descriptor for unlinkat() is not
                       AT_FDCWD or does not reference a directory.


       EPERM           The  named file is a directory; the 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 exe‐
                       cuted.


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

ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE  TYPEAT‐
       TRIBUTE  VALUE  _  Interface StabilityCommitted _ MT-LevelAsync-Signal-
       Safe


SEE ALSO
       rm(1), close(2), link(2), open(2), rmdir(2), remove(3C), attributes(7),
       fsattr(7), privileges(7)



Oracle Solaris 11.4               30 Nov 2015                        unlink(2)
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