comedi_buf_write_free(9)

💖 comedi_buf_write_free(9) 💖

okay so this is a page from the Kernel API Manual, and it's about comedi_buf_write_free — the "okay bestie I'm DONE writing, you can have the space back" function 🫶

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✨ NAME ✨

comedi_buf_write_free — free buffer space after it is written 💅

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🌸 SYNOPSIS 🌸

unsigned int comedi_buf_write_free (struct comedi_subdevice *s ,
       unsigned int nbytes );

literally that's the whole signature, no cap ✨

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🎀 ARGUMENTS 🎀

• s — the COMEDI subdevice. the main character of this call 🫶
• nbytes — max amount of space to free, in bytes. like a limit, bestie 🦋

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💜 DESCRIPTION 💜

So here's the vibe: this frees up to nbytes bytes of space that you previously reserved for writing in the COMEDI acquisition data buffer that belongs to the subdevice 🌈

And lowkey important: the amount of space actually freed is limited to the amount that was reserved — you can't free more than you took, bestie, that's not how any of this works 💀

The freed space is assumed to have been filled with sample data by the writer — like, that's the whole point, the writer did the thing and now we're handing it over 👑

Also!! if the samples in that freed space need to be "munged", do it here. this is the moment. this is the place. do the munge fr fr 🤏✨

After all that, the freed space becomes available for allocation by the reader — passing the baton, iconic behavior 🎀

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🔥 RETURN 🔥

The amount of space freed, in bytes. that's it, that's the number 💖

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👑 SEE ALSO 👑

• Kernel file ./drivers/comedi/comedi_buf.c
• comedi_buf_write_alloc(9)
• comedi_buf_read_n_available(9)
• comedi_buf_read_alloc(9)
• comedi_buf_read_free(9)
• comedi_buf_write_samples(9)
• comedi_buf_read_samples(9)

like the whole read/write alloc/free friend group, they all hang out together iykyk 🦋💫

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that's the whole page bestie, go free that buffer 💅✨

catch you later — this one's from ./drivers/comedi, dated October 2026, mwah 🫶💖