In 1.2.0-dev, mongoc_topology_select is responsible for selecting a server from your deployment for an operation. In pooled clients, if mongoc_topology_select doesn't know of a suitable server, it uses a condition variable to wait up to serverSelectionTimeoutMS for the monitor thread to discover one.

To use pthread_cond_wait, the driver begins by calculating the current time in milliseconds since the epoch:

   struct timeval tv;
   int64_t msec;

   bson_gettimeofday (&tv);
   msec = (tv.tv_sec * 1000) + (tv.tv_usec / 1000) + timeout_msec;

This works on platforms where tv_sec is a 64-bit int, but on Solaris it's 32 bits and overflows. (These days, representing tv_sec requires 31 bits, so multiplying it by 1000 overflows.)

The driver constructs a negative timespec from this calculation and passes it to pthread_cond_wait, which returns EINVAL and mongoc_topology_select quits.