Why define \0 as the first element of a char array in C?

Question

When I read BlueZ source code, I often see char arrays defined like this:

// bluez/android/sco-msg.h
static const char BLUEZ_SCO_SK_PATH[] = "\0bluez_sco_socket";

What good is it to define the first element as \\0 ?

Answer 1

In your particular case this array is used as pathname for a PF_LOCAL socket; see here . And leading NUL is used to point that address is an abstract one. From man 7 unix :

an abstract socket address is distinguished by the fact that sun_path[0] is a null byte ('\\0').

And this is the only reason why the first element is \\0 .