https://devzone.nordicsemi.com/f/nordic-q-a/32705/keil-structure-paddingHello, I am using the nRF52840 DK with Keil to develop. I have a structure defined as follows: I have verified that uint8 is 1 byte, uint16 is 2 bytes, and uint32 is 4 bytes. The size of struct multipart_header should be 16 bytes but it reportsen-USTelligent Community 13Fri, 23 Mar 2018 15:55:52 GMThttps://devzone.nordicsemi.com/thread/125789?ContentTypeID=1Fri, 23 Mar 2018 15:55:52 GMT137ad170-7792-4731-bb38-c0d22fbe4515:a1befbcc-8bd4-43fe-a12d-98b740791a4dTurbo J[quote userid="7768" url="~/f/nordic-q-a/32705/keil-structure-padding"]Is Keil padding this structure to a 32-bit boundary?[/quote] <p>Yes, and you usually want that even on a Cortex-M4F for performance reasons.</p> <p>One might be tempted to use &quot;packed&quot; struct (see compiler documentation), but in some cases you also need to fiddle with endian conversions, which means custom (de-)serialisation code.</p><div style="clear:both;"></div>