在C中将结构转换为char数组

Question

I have a struct defined below for the contents of a frame to be sent over uart.

I populate the frame using build_uart_frame() .

I have a function write_device() to transmit the frame over uart.

My question is, how do I pass the struct to write_device() as it is expecting a pointer to a char array.

Should I try convert the stuct variable rdata to a char array or am I approaching this wrong?

This question is related to another post that I have (I'm not sure if I your allowed do this). I understand that this is not a code writing service, I do try avoid asking questions but I'm a bit out of my depth.

That question is posted here: related question

Many thanks

typedef struct uart_frame {
  uint8_t sof;                    /* 1 byte  */
  uint8_t len;                    /* 1 bytes */
  uint8_t cmd0;                   /* 1 byte  */
  uint8_t cmd1;
  char data[11];                 
  unsigned char fcs;              /* 1 byte  */                      
} uart_frame_t;

//------------------------------------------------------------------------------
// Global uart frame
uart_frame_t rdata;
//------------------------------------------------------------------------------

// Populate the frame

int build_uart_frame() {

uart_frame_t *rd = &rdata; //pointer variable 'rd' of type uart_frame    

// common header codes
rd->sof = 0xFE;
rd->len = 11;
rd->cmd0 = 0x22;
rd->cmd0 = 0x05;
snprintf(rd->data, sizeof(rd->data), "%s", "Hello World");
rd->fcs = calcFCS((unsigned char *)rd, sizeof(uart_frame_t) - 1);
return 0;
}

//--------------------------------------------------------------------------
int write_device(char *txbuf, int size) {
DWORD BytesWritten;

  isolator_status = FT_Write(isolator_handle, txbuf, size, &BytesWritten); 
  if (isolator_status == FT_OK) {
    return 0;
  }
  return -1;

}
//--------------------------------------------------------------------------
int main() {

  build_uart_frame();
  write_device(??);

  return 0;
}

Answer 1

    int main() {


      char* tempBuf = (char*) &rdata;
      /* Clear the buffer*/
      memset( (char*)rdata, 0x00, sizeof(rdata));
      build_uart_frame();
      write_device(tempBuf, sizeof(uart_frame_t));
      /* You can have problem with BYTE alignement so you can check the result of sizeof(uart_frame_t) if it is really equal to declaration */


      return 0;

}