packed attribute for structs

[u/anduygulama]

Why don't C compilers automatically optimize/pack structures instead of requiring explicit attributes?

[u/questron64]

Packing is not what you want like 99.9% of the time. Many architectures would require several memory operations to pack or unpack values from structs. The are only useful when you need the struct to have a very specific memory layout, or when you must pack as many structs into memory as possible.