STRUCT COMEDI_INSN(9)

💖 struct comedi_insn(9) 💖

okay so bestie, welcome to the Kernel API Manual page for struct comedi_insn — yes it's a struct, yes it's from the kernel, and yes we're gonna get through it together 🫶

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✨ NAME ✨

struct comedi_insn — the COMEDI instruction, literally the little packet that tells a COMEDI subdevice what to do 💅

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🌸 SYNOPSIS 🌸

struct comedi_insn {
    unsigned int insn;
    unsigned int n;
    unsigned int __user *data;
    unsigned int subdev;
    unsigned int chanspec;
    unsigned int unused[3];
 };

look at her. six fields. absolutely iconic layout, no notes 💀✨

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🎀 Members 🎀

• insn — the COMEDI instruction type. it's the INSN_xxx situation, iykyk 👑
• n — the length of data[]. like how many things live in there 🍓
• data — a pointer to the data array that the instruction actually operates on. main character pointer energy fr fr ✨
• subdev — the subdevice index. which subdevice we're talking to, no cap 🦋
• chanspec — a packed "chanspec" value, and bestie it is packed, like it's carrying the channel number, the analog range index, the analog reference type, and flags all in one 💅 that's a lot of luggage for one unsigned int and she's handling it
• unused — reserved for future use. it's giving "saving your seat" 👀 literally just unused[3] sitting there for the future

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🌈 Description 🌈

so this struct is what you use with the COMEDI_INSN ioctl, and indirectly with the COMEDI_INSNLIST ioctl. indirect bestie, meaning it gets there through something else — we don't gatekeep 😌💖

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⭐ SEE ALSO ⭐

go read these next, they're all linked in the kernel file ./include/uapi/linux/comedi.h:

• enum comedi_subdevice_type(9)
• enum comedi_io_direction(9)
• enum configuration_ids(9)
• enum comedi_digital_trig_op(9)
• enum comedi_support_level(9)
• enum comedi_counter_status_flags(9)
• struct comedi_insnlist(9)
• struct comedi_cmd(9)
• struct comedi_chaninfo(9)
• struct comedi_rangeinfo(9)
• struct comedi_krange(9)
• struct comedi_subdinfo(9)
• struct comedi_devinfo(9)
• struct comedi_devconfig(9)
• struct comedi_bufconfig(9)
• struct comedi_bufinfo(9)

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that's the whole page, bestie, you ate that 🍽️💜

and yeah — this one lives in ./include/uapi/linux and it's dated October 2026, so mark your calendar and stan responsibly 🌸

kisses, mwah, go read a manpage 🎀🦋✨