问缺少使用libmodbus函数的示例

EN

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <modbus.h>

enum {TCP, RTU};

int main(int argc, char *argv[])
{
 int socket;
 modbus_t *ctx;
 modbus_mapping_t *mb_mapping;
 int rc;
 int use_backend;
 int i;
 uint16_t tab_reg[64];
 use_backend = RTU;

 printf("Waiting for Serial connection\n");
 ctx = modbus_new_rtu("/dev/SOLAR", 115200, 'N', 8, 1);
 modbus_set_slave(ctx, 0);
 //modbus_connect(ctx);
 if(modbus_connect(ctx) == -1)
  {
   fprintf(stderr, "Serial connection failed: 
            %s\n", modbus_strerror(errno));
   modbus_free(ctx);
   return -1;
  }

 printf("Serial connection started!\n");

 mb_mapping = modbus_mapping_new(MODBUS_MAX_READ_BITS, 0,
                                MODBUS_MAX_READ_REGISTERS, 0);
 if(mb_mapping == NULL)
  {
    fprintf(stderr, "Failed to allocate the mapping: %s\n",
              modbus_strerror(errno));
   modbus_free(ctx);
   return -1;
  }
  rc = modbus_read_input_registers(ctx, 1, 0x0A, tab_reg);
  if(rc == -1)
   {
    fprintf(stderr, "%s\n", modbus_strerror(errno));
    return -1;
   }

  for(i=0; i < rc; i++)
   printf("reg[%d]=%d (0x%X)\n", i, tab_reg[i], tab_reg[i]);
  modbus_mapping_free(mb_mapping);
  modbus_free(ctx);
  modbus_close(ctx);
  return 0;
}