import math.complex struct Cat { name string breed string age int } type Feline = Cat fn test_offsetof() { cat := Cat{ name: 'Cthulhu' breed: 'Great Old One' age: 2147483647 } unsafe { assert *(&string(&byte(&cat) + __offsetof(Cat, name))) == 'Cthulhu' assert *(&string(&byte(&cat) + __offsetof(Cat, breed))) == 'Great Old One' assert *(&int(&byte(&cat) + __offsetof(Cat, age))) == 2147483647 } } fn test_offsetof_struct_from_another_module() { num := complex.Complex{1.0, 1.0} unsafe { assert *(&f64(&byte(&num) + __offsetof(complex.Complex, re))) == 1.0 assert *(&f64(&byte(&num) + __offsetof(complex.Complex, im))) == 1.0 } } fn test_offsetof_alias() { fel := Feline{ name: 'Cthulhu' breed: 'Great Old One' age: 2147483647 } unsafe { assert *(&string(&byte(&fel) + __offsetof(Feline, name))) == 'Cthulhu' assert *(&string(&byte(&fel) + __offsetof(Feline, breed))) == 'Great Old One' assert *(&int(&byte(&fel) + __offsetof(Feline, age))) == 2147483647 } }