union {
        struct {
            uint32_t data:       8;                 /*GPIO32~39 output value*/
            uint32_t reserved8: 24;
        };
        uint32_t val;
    } out1;

/home/gustavo/Pro/open62541-arduino/arduino-1.8.6/hardware/espressif/esp32/tools/sdk/include/soc/soc/gpio_struct.h:31:13: error: width of 'reserved8' exceeds its type
             uint32_t reserved8: 24;
             ^