read value of a symbolic
char *restrict path, char
*restrict buf, size_t
fd, const char
*path, char *buf,
function places the contents of the symbolic link path
in the buffer buf, which has size
readlink() does not
NUL character to
function is equivalent to
readlink() except that
where path specifies a relative path, the symbolic
link whose contents are read is determined relative to the directory
associated with file descriptor fd instead of the
current working directory.
is passed the special value
AT_FDCWD (defined in
<fcntl.h>) in the
fd parameter, the current working directory is used
and the behavior is identical to a call to
The call returns the count of characters placed in the buffer if it succeeds, or a -1 if an error occurs, placing the error code in the global variable errno.
readlinkat() will fail if:
- A component of the path prefix is not a directory.
- A component of a pathname exceeded
NAME_MAXcharacters, or an entire pathname (including the terminating NUL) exceeded
- The named file does not exist.
- Search permission is denied for a component of the path prefix.
- Too many symbolic links were encountered in translating the pathname.
- The named file is not a symbolic link.
- An I/O error occurred while reading from the file system.
- buf or path extends outside the process's allocated address space.
readlinkat() will fail
- The path argument specifies a relative path and the
fd argument is neither
AT_FDCWDnor a valid file descriptor.
- The path argument specifies a relative path and the fd argument is a valid file descriptor but it does not reference a directory.
- The path argument specifies a relative path but search permission is denied for the directory which the fd file descriptor references.
lstat(2), stat(2), symlink(2), symlink(7)
readlinkat() functions conform to
IEEE Std 1003.1-2008 (“POSIX.1”).
readlink() system call first appeared
in 4.1cBSD. The
system call has been available since OpenBSD