va_list ap2;
va_copy(ap2, ap);
pthread_t self = __pthread_self();
if (self->dlerror_buf != (void *)-1)
free(self->dlerror_buf);
size_t len = vsnprintf(0, 0, fmt, ap2);
va_list ap2;
va_copy(ap2, ap);
pthread_t self = __pthread_self();
if (self->dlerror_buf != (void *)-1)
free(self->dlerror_buf);
size_t len = vsnprintf(0, 0, fmt, ap2);