CONNECTAT(2)

💅 CONNECTAT — like, the system call manual page, section 2 (System Calls Manual)

okay bestie, buckle up, we're doing a whole syscall today 🫶

✨ NAME ✨

connectat — initiate a connection on a socket 🌸

📚 LIBRARY 📚

Standard C Library (libc, -lc) — yeah she lives in libc, no cap 💖

🧚 SYNOPSIS 🧚

#include <sys/types.h>
#include <sys/socket.h>

#include <fcntl.h>

int
connectat(int fd, int s, const struct sockaddr *name,
    socklen_t namelen);

👑 DESCRIPTION 👑

So the connectat() system call initiates a connection on a socket. Main character behaviour, honestly 🔥

Here's the vibe: when you pass the special value AT_FDCWD in the fd parameter, the behaviour is identical to a call to connect(2). Same energy, same everything ✨

Otherwise, connectat() works like the connect(2) system call with two exceptions, and bestie, these two matter:

1. It is limited to sockets in the PF_LOCAL domain. That's it, that's the domain, no other domains invited to the party 💀
2. If the file path stored in the sun_path field of the sockaddr_un structure is a relative path, it is located relative to the directory associated with the file descriptor fd. So like, relative to your girl, not to wherever the process happens to be standing 🌈

🎀 RETURN VALUES 🎀

The connectat() function returns the value 0 if successful — slay 💅

Otherwise, the value -1 is returned and the global variable errno is set to indicate the error. Not the vibe, but that's how you'll know 😭

💀 ERRORS 💀

The connectat() system call may fail with the same errors as the connect(2) system call — yeah, all of them, go read that page — or with the following errors:

• [EBADF] — the sun_path field does not specify an absolute path and the fd argument is neither AT_FDCWD nor a valid file descriptor. Girl, that fd is not real 🙈
• [ENOTDIR] — the sun_path field is not an absolute path and fd is neither AT_FDCWD nor a file descriptor associated with a directory. Wrong kind of thing entirely, bestie 🍓

🦋 SEE ALSO 🦋

bindat(2), connect(2), socket(2), unix(4) — the whole friend group, go say hi 💜

⭐ AUTHORS ⭐

The connectat was developed by Pawel Jakub Dawidek <pawel@dawidek.net> under sponsorship from the FreeBSD Foundation. Iconic of them, fr fr 👑

and that's the page!! this one came from Debian, dated February 13, 2013, and it lives in the CONNECTAT(2) slot of the manual 💖