linux man page for fchmodat

FCHMODAT(2)						     Linux Programmer's Manual						       FCHMODAT(2)

NAME
       fchmodat - change permissions of a file relative to a directory file descriptor

SYNOPSIS
       #include <fcntl.h> /* Definition of AT_* constants */
       #include <sys/stat.h>

       int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       fchmodat():
	   Since glibc 2.10:
	       _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
	   Before glibc 2.10:
	       _ATFILE_SOURCE

DESCRIPTION
       The fchmodat() system call operates in exactly the same way as chmod(2), except for the differences described in this manual page.

       If  the	pathname  given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd
       (rather than relative to the current working directory of the calling process, as is done by chmod(2) for a relative pathname).

       If pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to the current working directory	of
       the calling process (like chmod(2)).

       If pathname is absolute, then dirfd is ignored.

       flags can either be 0, or include the following flag:

       AT_SYMLINK_NOFOLLOW
	      If pathname is a symbolic link, do not dereference it: instead operate on the link itself.  This flag is not currently implemented.

RETURN VALUE
       On success, fchmodat() returns 0.  On error, -1 is returned and errno is set to indicate the error.

ERRORS
       The same errors that occur for chmod(2) can also occur for fchmodat().  The following additional errors can occur for fchmodat():

       EBADF  dirfd is not a valid file descriptor.

       EINVAL Invalid flag specified in flags.

       ENOTDIR
	      pathname is relative and dirfd is a file descriptor referring to a file other than a directory.

       ENOTSUP
	      flags specified AT_SYMLINK_NOFOLLOW, which is not supported.

VERSIONS
       fchmodat() was added to Linux in kernel 2.6.16.

CONFORMING TO
       POSIX.1-2008.

NOTES
       See openat(2) for an explanation of the need for fchmodat().

SEE ALSO
       chmod(2), openat(2), path_resolution(7), symlink(7)

COLOPHON
       This  page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2009-12-13							       FCHMODAT(2)