QBRB.H(3)

💖 QBRB.H — the ring buffer page, but make it make sense 💖

okay bestie, this is qbrb.h, straight out of the libqb Programmer's Manual. it's a header, it's a whole vibe, and it's about to become your new hyperfixation. grab a snack. 🍓

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✨ NAME ✨

qbrb.h — this implements a ring buffer that works in "chunks", not bytes. periodt. 💅

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🎀 SYNOPSIS 🎀

#include <qb/qbrb.h>

that's it. that's the whole synopsis. iconic. 👑

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🦋 DESCRIPTION 🦋

so here's the tea: you write a complete chunk or you write nothing at all. no half-chunks, no lil byte-by-byte nibbling. it's giving all-or-nothing and honestly? respect. 😌

there are two types of ring buffer:

• normal — this one will refuse to write a new chunk if the ring buffer is full. it's full, it said what it said, no more room bestie. 💀
• overwrite — this one will reclaim the oldest chunks inorder to make way for the new ones. out with the old, in with the new, main character energy only. ✨

this implementation is capable of working across processes, BUT — and this is the important part — one process must only write and the other process read. one writer, one reader. that's the arrangement. do not test it. 🙈

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🌸 the read process will do the following:

rb = qb_rb_open("test2", 2000, QB_RB_FLAG_SHARED_PROCESS|QB_RB_FLAG_CREATE);
for (i = 0; i < 200; i++) {
try_read_again:
    l = qb_rb_chunk_read(rb, (void *)out, 32, 1000);
    if (l < 0) {
        goto try_read_again;
    }
}
...
qb_rb_close(rb);

look at that goto hopping back like it's got somewhere to be. it does. it's retrying. we love a persistent queen. 🫶

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🌈 the write process will do the following:

rb = qb_rb_open("test2", 2000, QB_RB_FLAG_SHARED_PROCESS);
for (i = 0; i < 200; i++) {
try_write_again:
    l = qb_rb_chunk_write(rb, &v, sizeof(v));
    if (l < sizeof(v)) {
        goto try_write_again;
    }
}
...
qb_rb_close(rb);

note how the writer did not pass QB_RB_FLAG_CREATE — because the reader already made it. teamwork, fr fr. 🧚

⚠️ reminder bestie: one process writes, the other reads. that's the whole deal. don't get cute with it.

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👑 SEE ALSO 👑

the whole friend group, go say hi:

• qb_rb_close(3)
• qb_rb_refcount_get(3)
• qb_rb_chmod(3)
• qb_rb_chown(3)
• qb_rb_open(3)
• qb_rb_write_to_file(3)
• qb_rb_create_from_file(3)
• qb_rb_chunks_used(3)
• qb_rb_chunk_reclaim(3)
• qb_rb_space_used(3)
• qb_rb_chunk_write(3)
• qb_rb_shared_user_data_get(3)
• qb_rb_chunk_commit(3)
• qb_rb_chunk_peek(3)
• qb_rb_space_free(3)
• qb_rb_name_get(3)
• qb_rb_chunk_alloc(3)
• qb_rb_chunk_read(3)

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💜 COPYRIGHT 💜

Copyright (C) 2010-2020 Red Hat, Inc.

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and that's the page bestie!! 🌟 it came from the LIBQB crew, dated 2025-09-16, and it lives at the address QBRB.H(3) — iykyk. go forth and buffer responsibly. mwah. 💋💖🎀