I like to use macros (in C) to spit out the structure size and offsets of each structure member over a serial port, in a format I can then cut-n-paste back into

I like to use macros (in C) to spit out the structure size and offsets of each structure member over a serial port, in a format I can then cut-n-paste back into the source. This output consists of a bunch of (compile-time, when possible) assertions so that any changes to a structure break the build. These assertions go on both the embedded side and the PC server side, so any weird packing issues show up at compile time.