Comment by neutrinobro

These days you don't have to worry about endianness much (unless you dealing with raw network packets). However, you do need to worry about byte-padding. Different compilers/systems will place byte padding between items in your struct differently (depending on the contents and ordering of items), and if you are not careful the in-memory or on-disk placement of struct data elements can be misaligned on different systems. Most systems align to a 8-byte boundary, but that isn't guaranteed.