mdb_put(3)

💖 mdb_put(3) — Write Flags 💖

okay bestie, welcome to the Library Functions Manual, this is the mdb_put page and it's giving flags energy. it's not a function, it's not a program — it's a whole lil' vibes-dump of macros and variables that the LMDB docs bundle together under the name mdb_put. let's get into it. 🦋

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✨ NAME ✨

mdb_put — Write Flags ✍️

no cap, that's literally it. it's the write flags, the little #defines you sprinkle on your puts and your cursor puts so the database knows what kind of moment you're having.

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🌸 SYNOPSIS 🌸

🎀 Topics

• Copy Flags — yes bestie, there's a whole topic just sitting here called that

🎀 Macros

these are the icons themselves, verbatim, do not touch:

#define MDB_NOOVERWRITE   0x10
#define MDB_NODUPDATA   0x20
#define MDB_CURRENT   0x40
#define MDB_RESERVE   0x10000
#define MDB_APPEND   0x20000
#define MDB_APPENDDUP   0x40000
#define MDB_MULTIPLE   0x80000

🎀 Variables

and here's the full roster of struct members that also live on this page for some reason. they didn't get their own page, so they're crashing here:

• size_t MDB_val::mv_size
• void * MDB_val::mv_data
• unsigned int MDB_stat::ms_psize
• unsigned int MDB_stat::ms_depth
• size_t MDB_stat::ms_branch_pages
• size_t MDB_stat::ms_leaf_pages
• size_t MDB_stat::ms_overflow_pages
• size_t MDB_stat::ms_entries
• void * MDB_envinfo::me_mapaddr
• size_t MDB_envinfo::me_mapsize
• size_t MDB_envinfo::me_last_pgno
• size_t MDB_envinfo::me_last_txnid
• unsigned int MDB_envinfo::me_maxreaders
• unsigned int MDB_envinfo::me_numreaders

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🌈 Detailed Description 🌈

💜 LMDB Command Line Tools 💜

so here's the thing — this page also shouts out the command line tools that ship with LMDB. here's the whole squad, no one gets left out:

• mdb_copy — environment copy tool 📋
• mdb_dump — environment export tool 📦
• mdb_load — environment import tool 📥
• mdb_stat — environment status tool 📊

iconic lineup honestly. main character energy across the board.

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💅 Macro Definition Documentation 💅

🌟 #define MDB_NOOVERWRITE 0x10

for put: don't write if the key already exists. like, if it's already there, leave it alone, we're not re-doing the bit. 🙈

🌟 #define MDB_NODUPDATA 0x20

only for MDB_DUPSORT. okay so there are two moods here:

• for put: don't write if the key and data pair already exist. same pair = we already have it, don't do it again.
• for mdb_cursor_del: remove all duplicate data items. all of them. periodt. 🧹

🌟 #define MDB_CURRENT 0x40

for mdb_cursor_put: overwrite the current key/data pair. right here, right now, over the one you're sitting on. 🔥

🌟 #define MDB_RESERVE 0x10000

for put: just reserve space for the data, don't copy it. and it hands you back a pointer to that reserved space so you can go fill it in yourself. it's giving diy. ✨

🌟 #define MDB_APPEND 0x20000

data is being appended, so don't split full pages. 🔗

🌟 #define MDB_APPENDDUP 0x40000

duplicate data is being appended, so don't split full pages. 🫶

🌟 #define MDB_MULTIPLE 0x80000

store multiple data items in one single call. only for MDB_DUPFIXED though — don't try it elsewhere bestie. 👑

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🦋 Variable Documentation 🦋

🌸 size_t MDB_val::mv_size

size of the data item 📏

🌸 void* MDB_val::mv_data

address of the data item 📍

🌸 unsigned int MDB_stat::ms_psize

size of a database page. and yes, this is currently the same for all databases. no favours. ✨

🌸 unsigned int MDB_stat::ms_depth

depth (height) of the B-tree 🌳

🌸 size_t MDB_stat::ms_branch_pages

number of internal (non-leaf) pages 🍓

🌸 size_t MDB_stat::ms_leaf_pages

number of leaf pages 🍃

🌸 size_t MDB_stat::ms_overflow_pages

number of overflow pages 🌊

🌸 size_t MDB_stat::ms_entries

number of data items 🔢

🌸 void* MDB_envinfo::me_mapaddr

address of map, if fixed 🗺️

🌸 size_t MDB_envinfo::me_mapsize

size of the data memory map 📐

🌸 size_t MDB_envinfo::me_last_pgno

ID of the last used page 🆔

🌸 size_t MDB_envinfo::me_last_txnid

ID of the last committed transaction ✅

🌸 unsigned int MDB_envinfo::me_maxreaders

max reader slots in the environment 🎟️

🌸 unsigned int MDB_envinfo::me_numreaders

max reader slots used in the environment 🎟️✨

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👑 Author 👑

generated automatically by Doxygen for LMDB from the source code. the robot did it, i just made it cute. 💖

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and that's the whole page bestie, every flag, every struct member, nothing skipped, iykyk 🫶

this lil' rewrite came to you from LMDB — the mdb_put(3) page, and that's the version and date situation, fr fr. slay, go write some flags. 💅🌈⭐