static size_t allocated_fluids_len = 0;
static scm_i_pthread_mutex_t fluid_admin_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER;
+SCM_PTHREAD_ATFORK_LOCK_STATIC_MUTEX (fluid_admin_mutex);
#define IS_FLUID(x) SCM_FLUID_P (x)
#define FLUID_NUM(x) SCM_I_FLUID_NUM (x)