peterGo, thanks. How can i use this kind of Go in windows? my machine is 64bit also. If I download the amd64 Go, the pointer size will be 8 bytes.
My real issue is , when I call win32 api, uint64 type in the struct of win32 is aligned to 8 bytes. I have to pad the go struct by manual to make it work with win32 api. best regards, xjdrew On Sunday, May 21, 2017 at 11:28:59 PM UTC+8, peterGo wrote: > > 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.
