OK, now I actually get it. Just use a CounterWriter and return bytes num it receives. Such writer already exists in the std lib?
在 2016年12月16日星期五 UTC+8下午2:10:41，P Q写道： > > 2016년 12월 16일 금요일 오전 11시 5분 53초 UTC+9, Peng Wang 님의 말: > Actually I don't really care about that, just don't want break the > interface requirement > in the doc it says "WriteAt writes len(p) bytes from p to the underlying > data stream at offset off. It returns the number of bytes written from p (0 > <= n <= len(p)) and any error encountered that caused the write to stop > early." > but using binary.Write I lost that infomation. So what's the right way to > do it ? or just ignore it and return 0? > > Write should inform the caller of the number of bytes written even though > some error happens during the write operation. ( > https://golang.org/pkg/io/#Writer states explicitly). It's recommended > for the WriteTo method to return a proper n, not 0. > > binary.Write dosen't return how many bytes are written, but not mean you > have to miss the information, because binary.Write calls internally to > io.Write. > > As Tamás Gulácsi says, you can wrap w in countWriter. And if error occurs, > examine countWriter.N field to get information about the number of bytes > written. > > I couldn't understand this wrapping could break the interface > requirements. The program you're writing need some even complicated > behavior i couldn't guess at? > -- 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.
