I don't know which one (not sure where macos is), but the macos constant for this is wrong. My system has:

```c
/*                                                                       
 * [XSI] Definitions for UNIX IPC domain.                                
 */                                                                      
struct  sockaddr_un {                                                    
        unsigned char   sun_len;        /* sockaddr len including null */
        sa_family_t     sun_family;     /* [XSI] AF_UNIX */              
        char            sun_path[104];  /* [XSI] path name (gag) */      
};                                                                       
```