diff --git a/lib/hostip.h b/lib/hostip.h
index 19a62c666dc0b172ce47f8800179a2f6bc1da32d..e0cc6beb4b93bf18ea86e94d7a48f2ba7d44ce96 100644
--- a/lib/hostip.h
+++ b/lib/hostip.h
@@ -121,7 +121,7 @@ void Curl_addrinfo_callback(void *arg,
 
 /* This is a utility-function for ipv4-builds to create a hostent struct
    from a numerical-only IP address */
-Curl_addrinfo *Curl_ip2addr(unsigned long num, char *hostname);
+Curl_addrinfo *Curl_ip2addr(in_addr_t num, char *hostname);
 
 /* relocate a hostent struct */
 void Curl_hostent_relocate(struct hostent *h, long offset);
diff --git a/lib/hostip4.c b/lib/hostip4.c
index bd6e40e736cefc62f5680d1b85140bd6b6267d03..92a76baeecdf1dc055818612de2393d8337e2abb 100644
--- a/lib/hostip4.c
+++ b/lib/hostip4.c
@@ -129,7 +129,7 @@ bool Curl_ipvalid(struct SessionHandle *data)
  * The input parameters ARE NOT checked for validity but they are expected
  * to have been checked already when this is called.
  */
-Curl_addrinfo *Curl_ip2addr(unsigned long num, char *hostname)
+Curl_addrinfo *Curl_ip2addr(in_addr_t num, char *hostname)
 {
   struct hostent *h;
   struct in_addr *addrentry;