Can you please explain that why it needs "__sync_synchronize()" in the source code? about cstring HOT 5 CLOSED

I guess memory barrier between cstring s and s->type is needed. maybe it's unusefu. Should I remove then?

from cstring.

I think here's not the situation '__sync_synchronize' needed. No memory ordering need to be guaranteed because you have used lock during interning cstring, which is the only share data in multithread. No where else can change s->type.
Anyway it affects little, removing it perhaps improve performance a little.

from cstring.

I mean

cstring 
cstring_persist(const char * cstr, size_t sz) {
    cstring s = cstring_clone(cstr, sz);
    if (s->type == 0) {
        s->type = CSTRING_PERMANENT;
        s->ref = 0;
    }
    __sync_synchronize();
    return s;
}

from cstring.

Do you worried about "return s" runs before "if (s->type == 0)" or "cstring_clone"?

But I can't tell the problem it cause without '__sync_synchronize();'.

from cstring.

yeah, maybe s was read by flowing cstring_grab() before s->type changed.

I'm not sure. But I guess I can remove these '__sync_synchronize();'

from cstring.