xjdrew, The Go Playground is (GOOS/GOARCH) nacl/amd64p32 which is a 64 bit architecture, where the address space is limited to a 4GB (32 bit) window. It has 8 byte (64 bit) data structure alignment.
linux/386 and windows/386 are 32 bit architectures, where the address space is 4GB (32 bit). They have 4 byte (32 bit) data structure alignment. Peter On Friday, May 19, 2017 at 7:28:54 AM UTC-4, xjdrew wrote: > > Hello everyone, > > > Code as below, playground url(https://play.golang.org/p/XSx--6uF0E): > > package main > > > import "fmt" > import "unsafe" > > > type A struct { > a uint8 > b uint64 > } > func main() { > a := &A{} > fmt.Println(unsafe.Sizeof(a)) > fmt.Println(unsafe.Sizeof(*a)) > } > > > When I run the code in go playground, I get what as i expected. > > > > 4 > 16 > > Program exited. > > > but when I test the code in my own environment(linux i386 & win32, both), I > get a unreasonable result as below: > > > $ go version > go version go1.8.1 linux/386 > $ go run align.go > 4 > 12 > > Then I test a similar code in C, the result is same as go playground. > > > typedef struct _aaa { UINT8 a; UINT64 b; }AAA; > > printf("%d",sizeof(int*)); // 4 > printf("%d",sizeof(AAA)); // 16 > > > uint64 should aligin in 8 bytes, why it aligns in 4 bytes in > go1.8.1.linux-386? > > Could anyone tell me how I can get the same result with go playground? > > > Best regards, > > drew > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
