C++ and SDK

RE: C++ and SDK

nick_haman — Thu, 06 Jan 2022 17:28:34 GMT

Understood. All other modules seem to work with C++ except usb_cdc_acm. This thread might help those in the future going down this path. It is a bit heavy handed modifying the SDK headers. It would be great it there was a cleaner fix to this issue.

RE: C++ and SDK

SwRa — Thu, 06 Jan 2022 16:00:34 GMT

Hi Nick,

It is a known issue that the macros used in the SDK are not well supported by C++. Our SDK is written to support C and some of the coding method is not well supported for C++. I will however ask around internally and will get back to you.

Kind Regards,

Swathy

RE: C++ and SDK

nick_haman — Wed, 05 Jan 2022 17:19:46 GMT

SDK 16.0 using usb_cdc_acm example. GCC with -std=C++11.

My workaround so far has been to place the above definition and callback function in a C module and to pass the arguments to the real callback in the C++ module.

Also, when including app_usbd_cdc_acm.h in the C++ module it complained about a forward enum declaration. I had to move the enum declaration into the app_usbd_cdc_acm_internal.h file and protect it with a #define:

#ifndef _APP_USBD_CDC_
#define _APP_USBD_CDC_


	typedef enum app_usbd_cdc_acm_user_event_e {
		APP_USBD_CDC_ACM_USER_EVT_RX_DONE, /**< User event RX_DONE.    */
		APP_USBD_CDC_ACM_USER_EVT_TX_DONE, /**< User event TX_DONE.    */

		APP_USBD_CDC_ACM_USER_EVT_PORT_OPEN, /**< User event PORT_OPEN.  */
		APP_USBD_CDC_ACM_USER_EVT_PORT_CLOSE, /**< User event PORT_CLOSE. */
	} app_usbd_cdc_acm_user_event_t;
	
#endif // !_APP_USBD_CDC_

/*lint -save -e165*/
/**
 * @brief Forward declaration of @ref app_usbd_cdc_acm_user_event_e.
 *
 */
enum app_usbd_cdc_acm_user_event_e;

RE: C++ and SDK

Nguyen Hoan Hoang — Wed, 05 Jan 2022 16:58:51 GMT

Data structure assignments must be in the order as the defined in the structure in C++. You need to re-order the assignments. For example.

typedef struct {
    int a;
    float b;
    char c;
} X_t;

// Wrong order, rejected by C++, accepted by C
X_t failedAssign = {
    .b = 1.0,
    .a = 3,
};

// Correct order, accepted by both
X_t goodAssign = {
    .a = 3;
    .b = 1.0,
};

Unfortunately there are a lot of those in the SDK.

RE: C++ and SDK

SwRa — Wed, 05 Jan 2022 16:04:29 GMT

Hi,

Which example are you trying to convert to C++.? Also, which compiler are you using.?

Regards,

Swathy

RE: C++ and SDK

nick_haman — Tue, 04 Jan 2022 20:46:17 GMT

Actually, when I convert it to int:

static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst, int event);

Error designator order for field 'app_usbd_cdc_acm_inst_t::comm_interface' does not match declaration order in 'app_usbd_cdc_acm_inst_t'

RE: C++ and SDK

nick_haman — Tue, 04 Jan 2022 20:44:09 GMT

Another error occurs in the APP_USBD_CDC_ACM_GLOBAL_DEF:

static void cdc_acm_user_ev_handler(app_usbd_class_inst_t const * p_inst, app_usbd_cdc_acm_user_event_t event);

/**
 * @brief CDC_ACM class instance
 * */
APP_USBD_CDC_ACM_GLOBAL_DEF(m_app_cdc_acm,
	cdc_acm_user_ev_handler,
	CDC_ACM_COMM_INTERFACE,
	CDC_ACM_DATA_INTERFACE,
	CDC_ACM_COMM_EPIN,
	CDC_ACM_DATA_EPIN,
	CDC_ACM_DATA_EPOUT,
	APP_USBD_CDC_COMM_PROTOCOL_AT_V250);

Error invalid conversion from 'void (*)(const app_usbd_class_inst_t*, app_usbd_cdc_acm_user_event_t)' {aka 'void (*)(const app_usbd_class_inst_s*, app_usbd_cdc_acm_user_event_e)'} to 'app_usbd_cdc_acm_user_ev_handler_t' {aka 'void (*)(const app_usbd_class_inst_s*, int)'}

Changing the event type to int gives another error about initialization.