不使用CGo将Go字符串转换为C字符串

Question

I'm trying to call some ioctls from Go, and some of them take C strings as parameters. For example, in C:

/* When the user asks to bind a message name to an interface, they use: */
struct kbus_bind_request {
    __u32 is_replier;   /* are we a replier? */
    __u32 name_len;
    char *name;
};

extern int kbus_ksock_bind(kbus_ksock_t         ksock,
                           const char          *name,
                           uint32_t             is_replier)
{
  int   rv;
  kbus_bind_request_t   bind_request;

  bind_request.name = (char *) name;
  bind_request.name_len = strlen(name);
  bind_request.is_replier = is_replier;

  rv = ioctl(ksock, KBUS_IOC_BIND, &bind_request);
  if (rv < 0)
    return -errno;
  else
    return rv;
}

I converted the struct to a Go struc like this:

type kbus_bind_request struct {
    is_replier uint32 /* are we a replier? */
    name_len   uint32
    name       unsafe.Pointer // char*
}

Now, how do I convert a Go string to a C string stored in an unsafe.Pointer? I don't want to use CGo as I am cross-compiling and it makes things a pain.

Answer 1

Ah found the answer (well something that compiles anyway). First cast to []byte, then take the address of the first element:

func int_bind(ksock int, name string, is_replier uint32) int {

    bind_request := &kbus_bind_request{}

    s := []byte(name)

    bind_request.name = unsafe.Pointer(&s[0])
    bind_request.name_len = uint32(len(s))
    bind_request.is_replier = is_replier

    rv := ioctl(ksock, KBUS_IOC_BIND, unsafe.Pointer(bind_request))

    if rv != 0 {
        return -int(rv)
    }
    return 0
}