nbd_set_pread_initialize(3)

💅 NAME 💅

okay so bestie, this page is all about nbd_set_pread_initialize — it controls whether libnbd pre-initializes read buffers. that's the whole vibe. ✨

this is part of the libnbd manual, btw, so you know where you are 🎀

---

🦋 SYNOPSIS 🦋

#include <libnbd.h>

int nbd_set_pread_initialize (
      struct nbd_handle *h, bool request
    );

---

🌸 DESCRIPTION 🌸

okay so here's the tea. ☕ by default, libnbd will pre-initialize the contents of a buffer passed to calls such as nbd_pread(3) to all zeroes prior to checking for any other errors. like, before anything else. and why? because even if a client application passed in an uninitialized buffer but then fails to check for errors, it won't result in a potential security risk caused by an accidental leak of prior heap contents. imagine the drama of leaking your old heap garbage — no thank you 🙈

for an example of a security hole in an application built against an earlier version of libnbd that lacked consistent pre-initialization, see CVE-2022-0485 in libnbd-security(3). yeah. that one. 💀

but listen — for a client application that has audited that an uninitialized buffer is never dereferenced, or which performs its own pre-initialization, libnbd's sanitization efforts merely pessimize performance. lowkey sad, highkey true. (although honestly, the time spent in pre-initialization may pale in comparison to time spent waiting on network packets, so don't @ me 🫶)

calling this function with "request" set to false tells libnbd to skip the buffer initialization step in read commands. periodt. ✨

---

⭐ RETURN VALUE ⭐

if the call is successful the function returns 0. slay. 👑

---

💜 ERRORS 💜

on error -1 is returned. 😭

refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

the following parameters must not be NULL: "h". for more information see "Non-NULL parameters" in libnbd(3). don't pass NULL bestie, i'm begging 🥺

---

🎀 VERSION 🎀

this function first appeared in libnbd 1.12. iconic behavior, honestly.

if you need to test if this function is available at compile time, check if the following macro is defined:

#define LIBNBD_HAVE_NBD_SET_PREAD_INITIALIZE 1

---

🌈 SEE ALSO 🌈

• nbd_aio_pread(3)
• nbd_aio_pread_structured(3)
• nbd_create(3)
• nbd_get_pread_initialize(3)
• nbd_pread(3)
• nbd_pread_structured(3)
• nbd_set_strict_mode(3)
• libnbd(3)

go read them, iykyk 📚💅

---

👑 AUTHORS 👑

• Eric Blake
• Richard W.M. Jones

these two? main character energy fr fr 🫶

---

🌸 COPYRIGHT 🌸

Copyright Red Hat

---

🧚 LICENSE 🧚

this library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

this library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. see the GNU Lesser General Public License for more details.

you should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

---

and that's the whole page, bestie 🍓 this lil beauty is from libnbd-1.25.8, dated 2026-10-13, and it's the nbd_set_pread_initialize(3) page — now go forth and don't leak your heap contents 💖✨🎀