socket_send6(3)

💌 socket_send6 — bestie's guide to yeeting a UDP datagram into the void ✨

okay so real talk, this is a page from the Library Functions Manual about socket_send6(3), and it's literally so good. sit down, grab a strawberry drink 🍓, and let's get into it.

---

🌸 NAME 🌸

socket_send6 — send a UDP datagram

---

🎀 SYNTAX 🎀

#include <libowfat/socket.h>

ssize_t socket_send6(int s, const char* buf, size_t len,
                     const char ip[16], uint16 port, uint32 scope_id);

---

🦋 DESCRIPTION 🦋

so here's the tea, bestie 💅 — socket_send6 sends len bytes starting at buf in a UDP datagram over the socket s to UDP port port on IP address ip. that's it, that's the whole vibe.

and here's the part that's giving convenience: you can call socket_send6 without calling socket_bind6 first. no cap. it has the same effect as first calling socket_bind6 with IP address :: and port 0. so like, you're covered either way, king 🫶

now, about scope_id — the meaning of it is dependent on the implementation and the IPv6 IP. on link-local IPv6 addresses it specifies the outgoing interface index. the name (e.g. "eth0") for a given interface index can be queried with getifname. and ngl, scope_id should normally be set to 0. periodt.

---

💖 RETURN VALUE 💖

socket_send6 returns 0 if the datagram was sent successfully. iconic. 💅

if not, it returns -1 and sets errno appropriately. 😭 so like, check your errno, bestie, it's literally telling you what went wrong.

---

✨ EXAMPLE ✨

here's the whole thing in action, no edits, exactly as written:

  #include <libowfat/socket.h>

  int s;
  char ip[16];
  uint16 p;
  uint32 scope_id;

  s = socket_tcp4();
  socket_bind6(s,ip,p);
  socket_send6(s,"hello, world",12,ip,p,scope_id);

look at her go 🧚 main character energy fr fr.

---

🌈 SEE ALSO 🌈

• socket_send4(3)
• socket_getifidx(3)

---

💀 heads up bestie: scope_id is implementation-dependent and you should normally just set it to 0. don't be out here guessing at interface indices for fun.

---

and that's the whole page, gorgeous. this one's from the Library Functions Manual, filed under socket_send6(3) — same name top and bottom, cute symmetry, we love to see it. mwah 💋 go send some datagrams responsibly.