diff --git a/lib/base64.c b/lib/base64.c
index 6b9331083f4ddfb1abe271751b8cafc66dda35a6..da9d01a93df322348e37c0086f3898373557e6fb 100644
--- a/lib/base64.c
+++ b/lib/base64.c
@@ -117,7 +117,7 @@ size_t Curl_base64_decode(const char *src, unsigned char **outptr)
   /* Decode all but the last quantum (which may not decode to a
   multiple of 3 bytes) */
   for(i = 0; i < numQuantums - 1; i++) {
-    decodeQuantum((unsigned char *)newstr, src);
+    decodeQuantum(newstr, src);
     newstr += 3; src += 4;
   }
 
@@ -153,7 +153,7 @@ size_t Curl_base64_encode(struct SessionHandle *data,
   char *convbuf = NULL;
 #endif
 
-  char *indata = (char *)inp;
+  const char *indata = inp;
 
   *outptr = NULL; /* set to NULL in case of failure before we reach the end */
 
diff --git a/lib/hostip.c b/lib/hostip.c
index 4e0df25466025587d564a1eaebe85cb8a10802c6..604dbbbdcb108a7f1b24e3f2aa0a024feb550712 100644
--- a/lib/hostip.c
+++ b/lib/hostip.c
@@ -619,7 +619,7 @@ Curl_addrinfo *Curl_ip2addr(in_addr_t num, const char *hostname, int port)
   h->h_aliases = NULL;
 
   /* Now store the dotted version of the address */
-  snprintf((char *)h->h_name, 16, "%s", hostname);
+  snprintf(h->h_name, 16, "%s", hostname);
 
 #if defined(VMS) && \
     defined(__INITIAL_POINTER_SIZE) && (__INITIAL_POINTER_SIZE == 64)
diff --git a/lib/ssh.c b/lib/ssh.c
index 95ce96fe74bb4a27276ef5183888402c728970d7..c86b2530c6148a3cca810e0f192e0e87e3a920a2 100644
--- a/lib/ssh.c
+++ b/lib/ssh.c
@@ -765,7 +765,7 @@ static CURLcode ssh_statemach_act(struct connectdata *conn)
     else if(rc > 0) {
       /* It seems that this string is not always NULL terminated */
       tempHome[rc] = '\0';
-      sshc->homedir = (char *)strdup(tempHome);
+      sshc->homedir = strdup(tempHome);
       if(!sshc->homedir) {
         state(conn, SSH_SFTP_CLOSE);
         sshc->actualcode = CURLE_OUT_OF_MEMORY;
diff --git a/lib/tftp.c b/lib/tftp.c
index 8478fd6f914adda5df2c524bec71a79fdfdfabcd..65c35427e5d08331288b722b7c94b22ab0db8770 100644
--- a/lib/tftp.c
+++ b/lib/tftp.c
@@ -803,7 +803,7 @@ static CURLcode tftp_do(struct connectdata *conn, bool *done)
           break;
         case TFTP_EVENT_ERROR:
           state->error = (tftp_error_t)getrpacketblock(&state->rpacket);
-          infof(data, "%s\n", (char *)&state->rpacket.data[4]);
+          infof(data, "%s\n", (const char *)&state->rpacket.data[4]);
           break;
         case TFTP_EVENT_ACK:
           break;