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.

       Since Linux 2.6.39, pathname can be an empty string, in which case the call operates on the file referred
       to by dirfd (which may have been obtained using the open(2) O_PATH flag).  In this case, dirfd can  refer
       to any type of file, not just a directory.

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; library support was added to glibc in version 2.4.

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 3.54 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/.