register_sysctl_sz(9)

💅 register_sysctl_sz(9) — kernel API manual, but make it make sense

okay bestie, so you know how sysctls are those little /proc/sys knobs everyone's obsessed with? this is the function that puts a whole table of them on the map. it's register_sysctl_sz from the kernel API manual, and yes, the sz is doing actual work here. let's go 🫶

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✨ SYNOPSIS ✨

struct ctl_table_header * register_sysctl_sz (const char *path , const
const struct ctl_table *table , size_t table_size );

no cap, that's the whole signature. take a sec. breathe. 🧚

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🎀 ARGUMENTS 🎀

• path — the path to the directory your sysctl table lives in. and here's the cute part: if the path doesn't exist, we will create it for you. built-in, no extra charge, we love a helpful function 💖
• table — the table structure itself. and this is the serious one, so listen up: the caller must ensure the life of the table is kept during the lifetime use of the sysctl. like, it must not be freed until unregister_sysctl_table is called with the table you got back from this registration. 💀 that's the whole contract, do not break it.

ngl there's a little escape hatch though: if your code is non modular, then you don't need to call unregister_sysctl_table at all, and you can instead use something like register_sysctl_init — which does not care for the result of the sysctl registration. bestie said "not my problem" and honestly? valid 🌸

• table_size — the number of elements in table. that's it. that's the size. 💅

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🦋 DESCRIPTION 🦋

so what does it do? it registers a sysctl table, obviously. your table should be a filled-in ctl_table array — a completely 0 filled entry terminates the table, so that's your stop sign, iykyk ⭐

for more details, go see __register_sysctl_table. that's where the actual lore lives 👑

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🌈 SEE ALSO 🌈

kernel file ./fs/proc/proc_sysctl.c — go read it, it's giving main character energy:

• register_sysctl_mount_point(9)
• get_subdir(9)
• __register_sysctl_table(9)
• __register_sysctl_init(9)
• unregister_sysctl_table(9)

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okay and that's the page! 🎀 this whole thing lives under ./fs/proc in the kernel tree, it's from the October 2026 era of the docs, and it's filed as register_sysctl_sz(9) in case you need to find it again. slay, go register some sysctls responsibly, and don't free that table early bestie I'm begging 🙈💜