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arduino

invalid conversion from 'int32_t {aka long int}' to 'const char*'

I am new to Arduino and think this might be easy but can't seem to solve it. I am getting an invalid conversion from 'int32_t {aka long int}' to 'const char*'

#include <BLEPeripheral.h>
constexpr int32_t file_maximum_byte_count = (50 * 1024);

BLECharacteristic file_maximum_length_characteristic = BLECharacteristic("3002", BLERead, sizeof(uint32_t));

In my setup I am doing this:

void setup() {
   ...
   blePeripheral.addAttribute(file_maximum_length_characteristic);
   file_maximum_length_characteristic.setValue(file_maximum_byte_count);
   ...
}

I guess I need to convert the file_maximum_length_characteristic to a const char* and on the bluetooth app receives this as an array I believe.

The error is happening on this line:

file_maximum_length_characteristic.setValue(file_maximum_byte_count);

Here is the library function information:

instance-method setValue → bool Parameters:

const unsigned char * value unsigned char length // In BLECharacteristic public: virtual bool setValue(const unsigned char value[], unsigned char length)

Although this doesn't make sense as I can pass in 1 value and have, but it doesn't work when I am receiving the value from the app when I do that.

Here is the GitHub repo of the library.

Solution

  • This worked for me:

    setValue((uint8_t*)&file_maximum_byte_count, sizeof(file_maximum_byte_count));