Examples of errors detected by the V1031 diagnostic

V1031. Function is not declared. The passing of data to or from this function may be affected.

RT-Thread

V1031 The 'strchr' function is not declared. Passing data to or from this function can be affected. dhcp_server_raw.c 718

#include <stdio.h>
#include <stdint.h>
// ....
void dhcpd_start(const char *netif_name)
{
  // ....
  char str_tmp[4 * 4 + 4] = DHCPD_SERVER_IP;
  char *p = str_tmp;
  ip4_addr_t ip_start, ip_end;

  p = strchr(str_tmp, '.');      // <=
  if (p)
  {
    p = strchr(p + 1, '.');      // <=
    if (p)
    {
      p = strchr(p + 1, '.');    // <=
    }
  }
  // ....
}

RT-Thread

V1031 The 'memcmp' function is not declared. Passing data to or from this function can be affected. dhcp_server_raw.c 151

#include <stdio.h>
#include <stdint.h>
// ....
static struct dhcp_client_node *
dhcp_client_find_by_mac
  (struct dhcp_server *dhcpserver, const u8_t *chaddr, u8_t hlen)
{
  struct dhcp_client_node *node;

  for (node = dhcpserver->node_list; node != NULL; node = node->next)
  {
    if (memcmp(node->chaddr, chaddr, hlen) == 0)               // <=
    {
      return node;
    }
  }

  return NULL;
}