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 3.25 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/.