es58x_check_msg_len(9)

✨ es58x_check_msg_len ✨

okay so real talk, this one lives in the Kernel API Manual and it's literally just the vibe check for your CAN messages 💅 like it's not deep, it's just making sure the message you got is exactly the size it said it was gonna be. no notes. iconic.

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🎀 NAME 🎀

es58x_check_msg_len — check the size of a received message. that's it. that's the whole job. queen of boundaries fr fr 🦋

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🌸 SYNOPSIS 🌸

es58x_check_msg_len (dev , msg , actual_len );

yes bestie, keep the spaces exactly like that, it's a macro thing, iykyk 💀

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💖 ARGUMENTS 💖

• dev — the device 🫶 it's only here so we can print error messages when stuff goes wrong. emotional support device, basically.
• msg — the received message. and listen, this one matters: it must not be a pointer ⚠️ like, not a pointer. don't do it. i'm serious 🙈
• actual_len — the length of the message as advertised in the command header. so this is what the message claims about itself. we're fact-checking it. 🔥

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🌈 DESCRIPTION 🌈

okay so first thing: this must be a macro. why? because it has to accept the different types of messages as an input, and a regular function just can't do that for you, sorry babe 😭

it can be used with any of the messages that have a fixed length — those are its people, its main character messages 👑

and what does it actually do? it checks for an exact match of the size. not "close enough", not "roughly", not "vibes are right". exact. match. periodt 💅

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⭐ RETURN ⭐

• zero on success 🎉 slay, the size was correct, we move
• -EMSGSIZE if actual_len differs from the expected length 💀 yeah that's a fail, the message lied about its length, we're calling it out

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🦋 SEE ALSO 🦋

okay bestie, this list is long but every single one of these is part of the family, so here we go:

kernel file ./drivers/net/can/usb/etas_es58x/es58x_core.h, enum es58x_driver_info(9), enum es58x_physical_layer(9), enum es58x_sync_edge(9), enum es58x_flag(9), enum es58x_err(9), enum es58x_event(9), struct es58x_priv(9), struct es58x_parameters(9), struct es58x_operators(9), struct es58x_sw_version(9), struct es58x_hw_revision(9), struct es58x_device(9), es58x_sizeof_es58x_device(9), es58x_check_msg_max_len(9), es58x_msg_num_element(9), es58x_priv(9), ES58X_SIZEOF_URB_CMD(9), es58x_get_urb_cmd_len(9), es58x_get_netdev(9), es58x_get_raw_can_id(9), es58x_get_flags(9)

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ngl the -EMSGSIZE thing is the whole personality of this macro. check your lengths, bestie. 🍓

and that's the page!! mwah 💋 this little writeup lives in ./drivers/net/can/usb/etas_es58x, dated October 2026, and it's filed under es58x_check_msg_len(9) — periodt, go check your message sizes, ily bye 🧚💜