go/src/os/zero_copy_posix.go

// wrapSyscallError takes an error and a syscall name. If the error is
// a syscall.Errno, it wraps it in an os.SyscallError using the syscall name.
func wrapSyscallError(name string, err error) error { … }

// tryLimitedReader tries to assert the io.Reader to io.LimitedReader, it returns the io.LimitedReader,
// the underlying io.Reader and the remaining amount of bytes if the assertion succeeds,
// otherwise it just returns the original io.Reader and the theoretical unlimited remaining amount of bytes.
func tryLimitedReader(r io.Reader) (*io.LimitedReader, io.Reader, int64) { … }