BSON_NEW_FROM_BUFFER(3)

💅 BSON_NEW_FROM_BUFFER(3) 💅

okay bestie, welcome to the libbson corner of the manual — this one's the bson_new_from_buffer page and honestly it's giving "wrap your existing buffer in a shiny new bson_t" energy ✨

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✨ SYNOPSIS ✨

bson_t *
bson_new_from_buffer (uint8_t **buf,
                      size_t *buf_len,
                      bson_realloc_func realloc_func,
                      void *realloc_func_ctx);

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🎀 PARAMETERS 🎀

• buf — an out-pointer pointing at a buffer that's holding a serialized BSON document, or it points at NULL. yep, either situation is legal, she's flexible 💅
• buf_len — an out-pointer to how long that buffer is, in bytes 📏
• realloc_func — optional bson_realloc_func that gets used for reallocating the buffer. optional!! but iconic when you bring it 🫶
• realloc_func_ctx — optional pointer that'll be handed to realloc_func as the ctx argument

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🦋 DESCRIPTION 🦋

So basically: this function creates a brand-new bson_t out of the data you already have. no copying drama, just vibes 🌸

The realloc_func, if you provide it, gets called to resize buf whenever the document later gets expanded — like, say, when you call one of the bson_append functions. she grows, she calls your allocator, that's the whole deal ✨

If *buf starts out as NULL, then it gets allocated (using realloc_func, or the default allocator if you didn't pass one) and initialized with an empty BSON document. and then *buf_len is set to 5 — yup, 5, that's literally the size of an empty document, no cap 🔥

If *buf is initially non-NULL, then *buf_len must be at least as large as the embedded length sitting in the first four bytes of the BSON data in *buf — but it's totally fine if it's bigger than that. any leftover buffer capacity can be used later to grow the BSON document. room to grow = main character energy 👑

lowkey important: that "at least as large as" bit is a real requirement, not a suggestion. the embedded length in the first four bytes is the vibe check your buffer has to pass 💀

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⭐ RETURNS ⭐

A newly-allocated bson_t if everything slayed, or NULL if it didn't 😭

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🌈 AUTHOR 🌈

MongoDB, Inc — love them for this fr fr 💜

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🧚 COPYRIGHT 🧚

2009-present, MongoDB, Inc.

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and that's the whole page, bestie 🎀 this was BSON_NEW_FROM_BUFFER(3) from the libbson manual, version 2.5.6, dated Oct 09, 2026 — go forth and wrap those buffers 👑💖