explain_readv_or_die(3)

💖 explain_readv_or_die — the manual, but make it make sense 💖

okay so bestie, we're looking at explain_readv_or_die(3) from the Library Functions Manual — yes it's a section 3 page, library functions, we love her for that 💅

---

✨ NAME ✨

explain_readv_or_die — read data into multiple buffers and report errors

like... that's the whole gig. you read into multiple buffers, and if it goes wrong, somebody tells you. iconic behaviour honestly 🫶

---

🌸 SYNOPSIS 🌸

#include <libexplain/readv.h>
ssize_t explain_readv_or_die(int fildes, const struct iovec *iov, int
iovcnt);
ssize_t explain_readv_on_error(int fildes, const struct iovec *iov, int
iovcnt);

two functions, two vibes. one of them does NOT come back on failure. guess which 🙈

---

🦋 DESCRIPTION 🦋

so the explain_readv_or_die function is used to call the readv(2) system call. and the way that it handles failure?? it prints an explanation to stderr, obtained from the explain_readv(3) function, and then — and this is the dramatic part — the process terminates by calling exit(EXIT_FAILURE). no survivors. main character energy fr fr 💀

the explain_readv_on_error function is also used to call the readv(2) system call. on failure, it prints an explanation to stderr, obtained from the explain_readv(3) function, but it still returns to the caller. so it's giving "I told you what went wrong, now deal with it yourself" 💅

now the arguments, bestie, and yes they're all literally "exactly as to be passed to the readv(2) system call", that's the whole point:

• fildes — the fildes, exactly as to be passed to the readv(2) system call.
• iov — the iov, exactly as to be passed to the readv(2) system call.
• iovcnt — the iovcnt, exactly as to be passed to the readv(2) system call.

no secret sauce, no remixing, no extra seasoning. you hand them over as-is 🎀

---

⭐ RETURN VALUE ⭐

• the explain_readv_or_die function only returns on success, see readv(2) for more information. on failure, it prints an explanation and exits — it does not return. like, at all. bye 👋
• the explain_readv_on_error function always returns the value return by the wrapped readv(2) system call. every single time. that's her whole personality 🌈

---

🍓 EXAMPLE 🍓

the explain_readv_or_die function is intended to be used in a fashion similar to the following example:

ssize_t result = explain_readv_or_die(fildes, iov, iovcnt);

one line. that's it. that's the whole tutorial. slay ✨

---

👑 SEE ALSO 👑

• readv(2) — read data into multiple buffers
• explain_readv(3) — explain readv(2) errors
• exit(2) — terminate the calling process

iykyk, these three are the friend group 🫶

---

💜 COPYRIGHT 💜

libexplain version 1.4 Copyright (C) 2009 Peter Miller

---

okay that's the whole page, bestie!! now go read into those multiple buffers responsibly 💖

and that's a wrap on explain_readv_or_die(3) — courtesy of libexplain version 1.4, Copyright (C) 2009 Peter Miller, and the Library Functions Manual. mwah 😘💅