unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (SunOS-5.10)
Page:
Section:
Apropos / Subsearch:
optional field

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(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 argu-
       ment is unused. If path is relative and dirfd has the  value  AT_FDCWD,
       defined  in  <&lt;fcntl.h>&gt;,  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
       <&lt;fcntl.h>&gt;, 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.

       The path argument must not name a  directory  unless  the  process  has
       appropriate  privileges  and the implementation supports using unlink()
       and unlinkat() on directories.

       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.



       EFAULT          The path argument points to an illegal address.



       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 and {PRIV_SYS_LINKDIR} is
                       not asserted  in  the  effective  set  of  the  calling
                       process.



       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(5) for descriptions of the following attributes:


       tab()     allbox;     cw(2.750000i)|    cw(2.750000i)    lw(2.750000i)|
       lw(2.750000i).  ATTRIBUTE  TYPEATTRIBUTE  VALUE  Interface  StabilityT{
       unlink()  is  Standard; unlinkat() is Evolving T} MT-LevelAsync-Signal-
       Safe


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




SunOS 5.10                        1 Feb 2003                         unlink(2)