Calling evthread_use_pthreads() after calling ev_base_new()

[tohava]

libevent allows doing this, which causes bugs, since locks are sometimes used and sometimes not. I would expect that at least with the debug flag on, I will get an error message for this.

[nmathewson]

That's a fine idea. I'd be glad to apply a patch for this.

[ghazel]

+1 for at least an error message, if it's not possible to make it just work. I ran in to this bug today.

[errzey]

Off the top of my head, I would suggest using event_enable_debug_mode type features:

#ifndef EVENT__DISABLE_DEBUG_MODE
int event_base_created_ = 0;
#endif

/* .... */

struct event_base *
event_base_new_with_config(const struct event_config *cfg) 
{
       /* ... */
#ifndef EVENT__DISABLE_DEBUG_MODE
        if (event_debug_mode_on_)
            event_base_created_ += 1;
#endif
       /* ... */
}

/* ..... */

int
evthread_use_pthreads(void)
{
#ifndef EVENT__DISABLE_DEBUG_MODE
        if (event_debug_mode_on_ && event_base_created_) 
           event_errx(1, "evthread_use_pthreads must be called BEFORE any events")
#endif
        /* .... */
}

[errzey]

#251 Merged