PVR_IOCTL_U...ADDING_CHECK(9)

💅 PVR_IOCTL_UNION_PADDING_CHECK — Kernel API Manual ✨

okay bestie, so this one is from the Kernel API Manual, and it's literally a vibe check for union padding. it checks that the implicit padding between the end of a union member and the end of the union itself is all zeroed out. no sneaky garbage bytes allowed, periodt. 🎀

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✨ NAME ✨

PVR_IOCTL_UNION_PADDING_CHECK — validate that the implicit padding between the end of a union member and the end of the union itself is zeroed. that's it, that's the whole job, and it does it flawlessly. 💖

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🦋 SYNOPSIS 🦋

PVR_IOCTL_UNION_PADDING_CHECK (struct_instance_ , union_ , member_ );

three arguments, that's all. slay. ✨

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🌸 ARGUMENTS 🌸

• struct_instance_ — an expression which evaluates to a pointer to a UAPI data struct. lowkey just hand it your struct pointer and it's happy. 🫶
• union_ — the name of the union member of struct_instance_ to check. oh and heads up: if the union member is nested within the type of struct_instance_, this may contain the member access operator ("."). iykyk. 🔥
• member_ — the name of the member of union_ to assess. the one we're actually judging. 👑

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💅 DESCRIPTION 💅

this is a wrapper around pvr_ioctl_union_padding_check which performs alignment checks and simplifies things for the caller. so it's giving "convenience layer" and honestly? iconic of it. it does the tedious alignment math so you don't have to, and you just get to live your main character life. 💜

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⭐ RETURN ⭐

• true if every byte in struct_instance_ between the end of member_ and the end of union_ is zeroed, or
• false otherwise.

so like... a literal boolean vibe check. it ate. 🌈

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💀 SEE ALSO 💀

Kernel file ./drivers/gpu/drm/imagination/pvr_device.h struct pvr_gpu_id(9), struct pvr_fw_version(9), struct pvr_device_data(9), struct pvr_device(9), struct pvr_file(9), PVR_HAS_FEATURE(9), PVR_FEATURE_VALUE(9), PVR_HAS_QUIRK(9), PVR_HAS_ENHANCEMENT(9), PVR_PACKED_BVNC(9), pvr_gpu_id_to_packed_bvnc(9), PVR_CR_FIELD_GET(9), pvr_cr_read32(9), pvr_cr_read64(9), pvr_cr_write32(9), pvr_cr_write64(9), pvr_cr_poll_reg32(9), pvr_cr_poll_reg64(9), pvr_round_up_to_cacheline_size(9), IOCTL validation helpers(9), pvr_ioctl_union_padding_check(9), PVR_STATIC_ASSERT_64BIT_ALIGNED(9)

like yes that's a lot of friends but every single one of them is invited to the group chat. 🙈

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okay that's the whole page bestie, no cap. it lives in ./drivers/gpu/drm/imagination, it's dated October 2026, and it goes by PVR_IOCTL_U...ADDING_CHECK(9). mwah 💋 🍓