The seg fault can be worked around if the nested designated initializer is removed: static struct cfg config[] = {     // the first definition makes the segmentation fault. Comment it and everything is fine.     { .module_id = MODULE_1,       .param_length = sizeof(struct module_1_params),       .param = (struct module_1_params []){{1}} /* remove this designated initializer */     },     { .module_id = MODULE_2,       .param_length = 5,       .param = (int[]){0,1,2,3,4}     },     { .module_id = MODULE_3,       .param_length = 2,       .param = (int[]){0,1}     } };