UNION PIPE_INDEX(9)

💖 union pipe_index(9) 💖

straight outta the Kernel API Manual, it's union pipe_index(9) — the page all about pipe indeces (yes, spelled like that, and we're keeping it because it's iconic). 💅

🦋 NAME 🦋

union pipe_index — pipe indeces.

✨ SYNOPSIS ✨

okay so here's the whole struct, bestie, copied exactly:

union pipe_index {
    unsigned long head_tail;
    struct {
      pipe_index_t head;
      pipe_index_t tail;
    };
 };

🌸 Members 🌸

the field breakdown, no cap:

• head_tail — an unsigned long union of head and tail — one field carrying the whole situation.
• {unnamed_struct} — anonymous. no name, just mystery and vibes.
• head — the point of buffer production. periodt.
• tail — the point of buffer consumption. also periodt.

🔮 SEE ALSO 🔮

the whole friend group is right here:

• Kernel file ./include/linux/pipe_fs_i.h
• struct pipe_buffer(9)
• struct anon_pipe_prealloc(9)
• struct pipe_inode_info(9)
• pipe_has_watch_queue(9)
• pipe_occupancy(9)
• pipe_empty(9)
• pipe_full(9)
• pipe_is_full(9)
• pipe_is_empty(9)
• pipe_buf_usage(9)
• pipe_buf(9)
• pipe_head_buf(9)
• pipe_buf_get(9)
• pipe_buf_release(9)
• pipe_buf_confirm(9)
• pipe_buf_try_steal(9)

signed off with love from ./include/linux — October 2026 edition 🎀✨