BSON_APPEND_BINARY_UNINIT(3)

💅 BSON_APPEND_BINARY_UNINIT(3) ✨

okay bestie, so this one is a page from the libbson manual, and it's literally called BSON_APPEND_BINARY_UNINIT — say that five times fast, i dare you. it's giving "i know what i'm doing" main character energy, so let's get into it 🫶

---

🌸 SYNOPSIS 🌸

so first up, there's a macro, and macros are lowkey just shortcuts with extra steps:

#define BSON_APPEND_BINARY_UNINIT(b, key, subtype, val, len) \
   bson_append_binary_uninit (b, key, (int) strlen (key), subtype, val, len)

and then the actual function it wraps, which is the real icon here:

bool
bson_append_binary_uninit (bson_t *bson,
                           const char *key,
                           int key_length,
                           bson_subtype_t subtype,
                           uint8_t **binary,
                           uint32_t length);

yes bestie, two stars on uint8_t **binary — that's the whole point of this function, we'll get there 💖

---

🎀 PARAMETERS 🎀

• bson — a bson_t. that's your document, your canvas, your whole vibe ✨
• key — the key name. name your field something cute.
• key_length — the length of key in bytes, or -1 to just let strlen() handle it. -1 is the "i trust you, bestie" option.
• subtype — a bson_subtype_t that says which binary subtype this is. gotta label your stuff 🏷️
• binary — location for a pointer that will receive a writable pointer to the uninitialized binary data block. yes — uninitialized. it's a blank canvas, no cap.
• length — the length of buffer in bytes.

---

🦋 DESCRIPTION 🦋

okay so bson_append_binary_uninit() is the alternative to bson_append_binary() — she's the cool cousin 😎 — and what she does is let applications assemble the contents of the binary field within the bson_t, without an additional temporary buffer. no middleman, no extra allocation, we love efficiency 💅

⚠️ but listen — on success, the caller MUST write to every byte of the binary data block if the resulting bson_t is to be used. every. single. byte. bestie. don't leave any of it uninitialized and then act surprised 😭

and one more thing, the buffer that binary points to is only valid until the iterator's bson_t is otherwise modified or freed. so like… use it now or lose it forever. it's giving limited-edition drop 🌈

---

🔥 RETURNS 🔥

returns true if the uninitialized binary item was appended — slay 🎉

the function will fail if appending binary grows bson larger than INT32_MAX. like, she has limits, okay? we all do 💀

---

💜 AUTHOR 💜

MongoDB, Inc — icons only 👑

⭐ COPYRIGHT ⭐

2009-present, MongoDB, Inc. — protect the legacy 🫡

---

and that's the whole page, bestie — no notes, ate and left no crumbs 🍓

signing off with all the deets: this was BSON_APPEND_BINARY_UNINIT(3) from libbson, version 2.5.6, dated Oct 09, 2026 💖 see you in the next manpage, love u!! ✨