find_first_andnot_bit(9)

💖 find_first_andnot_bit(9) 💖

okay bestie, welcome to the Kernel API Manual — today's main character is literally find_first_andnot_bit(9). It's giving "find me a bit that's set in one bitmap and unset in the other" energy. 🦋

🌸 NAME 🌸

find_first_andnot_bit — find the first bit set in 1st memory region and unset in 2nd.

✨ SYNOPSIS ✨

Here's the exact signature, no cap:

unsigned long find_first_andnot_bit (const unsigned long *addr1 , const unsigned long *addr2 , unsigned long size );

🎀 ARGUMENTS 🎀

• addr1 — the first address to base the search on. Like, search headquarters #1. 💅
• addr2 — the second address to base the search on. Search headquarters #2, bestie.
• size — the bitmap size in bits. Yep, bits, periodt. 🫶

💜 DESCRIPTION 💜

It returns the bit number for the first set bit, iykyk. And if no bits are set, it returns >= size. That's the whole vibe check: first set bit in the first memory region that's unset in the second, or a value >= size when there's nothing to find. 😭✨

🌈 SEE ALSO 🌈

Kernel file ./include/linux/find.h is the spot to peek at, and these cuties are all linked from the same crew:

• find_next_bit(9)
• find_next_and_bit(9)
• find_next_andnot_bit(9)
• find_next_or_bit(9)
• find_next_zero_bit(9)
• find_first_bit(9)
• find_nth_bit(9)
• find_nth_and_bit(9)
• find_nth_and_andnot_bit(9)
• find_first_and_bit(9)
• find_first_and_and_bit(9)
• find_first_zero_bit(9)
• find_last_bit(9)
• find_next_and_bit_wrap(9)
• find_next_bit_wrap(9)
• find_next_clump8(9)
• for_each_set_bitrange(9)
• for_each_set_bitrange_from(9)
• for_each_clear_bitrange(9)
• for_each_clear_bitrange_from(9)
• for_each_set_bit_wrap(9)
• for_each_set_clump8(9)

Cute sign-off time: this page's source/version spot is ./include/linux, it's dated October 2026, and it's literally the find_first_andnot_bit(9) manual page. Bye bestie, go find those bits! 💅✨