#include <fcntl.h> /* Definition of AT_* constants */
int readlinkat(int dirfd, const char *pathname,
char *buf, size_t bufsiz);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
Since glibc 2.10:
_XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
Before glibc 2.10:
The readlinkat() system call operates in exactly the same way as read-
link(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.
On success, readlinkat() returns the number of bytes placed in buf. On
error, -1 is returned and errno is set to indicate the error.
The same errors that occur for readlink(2) can also occur for read-
linkat(). The following additional errors can occur for readlinkat():
EBADF dirfd is not a valid file descriptor.
pathname is relative and dirfd is a file descriptor referring to
a file other than a directory.
readlinkat() was added to Linux in kernel 2.6.16; library support was
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/.
Linux 2013-07-31 READLINKAT(2)
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