pack(9)

okay bestie, welcome to pack(9) from the Kernel API Manual ✨ this one is all about tucking a u64 into a bitfield inside a buffer, and honestly? iconic. 💅

🌸 NAME 🌸

pack — pack a u64 number into a bitfield of a buffer. 🎀

✨ SYNOPSIS ✨

int pack (void *pbuf , u64 uval , size_t startbit , size_t endbit ,
       size_t pbuflen , u8 quirks );

🫶 ARGUMENTS 🫶

• pbuf — pointer to a buffer holding the packed value. this is the zone where the packed bits live, bestie. 💖
• uval — the CPU-readable unpacked value to pack. yes, this is the u64 main character. 👑
• startbit — the index (in logical notation, compensated for quirks) where the packed value starts within pbuf. it must be larger than, or equal to, endbit. no cap. ⭐
• endbit — the index (in logical notation, compensated for quirks) where the packed value ends within pbuf. it must be smaller than, or equal to, startbit. 💀
• pbuflen — the length in bytes of the packed buffer pointed to by pbuf. keep that size accurate, bestie. 📏
• quirks — a bit mask of QUIRK_LITTLE_ENDIAN, QUIRK_LSW32_IS_FIRST and QUIRK_MSB_ON_THE_RIGHT. it’s giving “personality settings” for your packing. 🌈

💖 RETURN 💖

0 means success, bestie. 🎉 if you called it incorrectly, you get EINVAL or ERANGE. assuming correct usage, the return code may be discarded. on success, the pbuf memory will be modified. lowkey important: the memory does change, so don’t act surprised. 💅

🌟 SEE ALSO 🌟

the kernel file ./lib/packing.c, plus these iconique functions: calculate_box_addr(9), unpack(9), packing(9), pack_fields_u8(9), pack_fields_u16(9), unpack_fields_u8(9), unpack_fields_u16(9). go read them if you want the full lore. 📚✨

mwah 💋 — signing off from ./lib, October 2026, on the pack(9) page. periodt. 🫶🎀