linux man page for readlinkat

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

NAME
       readlinkat - read value of a symbolic link relative to a directory file descriptor

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

       int readlinkat(int dirfd, const char *pathname,
		      char *buf, size_t bufsiz);

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

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

DESCRIPTION
       The readlinkat() system call operates in exactly the same way as readlink(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 readlink(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 readlink(2)).

       If pathname is absolute, then dirfd is ignored.

RETURN VALUE
       On success, readlinkat() returns the number of bytes placed in buf.  On error, -1 is returned and errno is set to indicate the error.

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

       EBADF  dirfd is not a valid file descriptor.

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

VERSIONS
       readlinkat() 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 readlinkat().

SEE ALSO
       openat(2), readlink(2), path_resolution(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							     READLINKAT(2)