@@ -71,11 +71,10 @@
  *
  *-------------------------------------------------------------------
  */
 static int TlsCloseProc(ClientData instanceData, Tcl_Interp *interp) {
     State *statePtr = (State *) instanceData;
-    (void) interp;
 
     dprintf("TlsCloseProc(%p)", (void *) statePtr);
 
     Tls_Clean(statePtr);
     Tcl_EventuallyFree((ClientData)statePtr, Tls_Free);
@@ -152,11 +151,10 @@
 	    err = SSL_connect(statePtr->ssl);
 	}
 
 	if (err > 0) {
 	    dprintf("Accept or connect was successful");
-
 	    err = BIO_flush(statePtr->bio);
 	    if (err <= 0) {
 		dprintf("Flushing the lower layers failed, this will probably terminate this session");
 	    }
 	} else {
@@ -217,11 +215,10 @@
 	    return(-1);
 
 	case SSL_ERROR_SYSCALL:
 	    /* Some non-recoverable, fatal I/O error occurred */
 	    dprintf("SSL_ERROR_SYSCALL");
-
 	    if (backingError == 0 && err == 0) {
 		dprintf("EOF reached")
 		*errorCodePtr = ECONNRESET;
 		Tls_Error(statePtr, "(unexpected) EOF reached");
 
@@ -229,32 +226,32 @@
 		dprintf("I/O error occurred (errno = %lu)", (unsigned long) Tcl_GetErrno());
 		*errorCodePtr = Tcl_GetErrno();
 		if (*errorCodePtr == ECONNRESET) {
 		    *errorCodePtr = ECONNABORTED;
 		}
-		Tls_Error(statePtr, Tcl_ErrnoMsg(Tcl_GetErrno()));
+		Tls_Error(statePtr, (char *) Tcl_ErrnoMsg(Tcl_GetErrno()));
 
 	    } else {
 		dprintf("I/O error occurred (backingError = %lu)", backingError);
 		*errorCodePtr = backingError;
 		if (*errorCodePtr == ECONNRESET) {
 		    *errorCodePtr = ECONNABORTED;
 		}
-		Tls_Error(statePtr, ERR_reason_error_string(backingError));
+		Tls_Error(statePtr, (char *) ERR_reason_error_string(backingError));
 	    }
 
 	    statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
 	    return(-1);
 
 	case SSL_ERROR_SSL:
 	    /* A non-recoverable, fatal error in the SSL library occurred, usually a protocol error */
 	    dprintf("SSL_ERROR_SSL: Got permanent fatal SSL error, aborting immediately");
 	    if (backingError != 0) {
-		Tls_Error(statePtr, ERR_reason_error_string(backingError));
+		Tls_Error(statePtr, (char *) ERR_reason_error_string(backingError));
 	    }
 	    if (SSL_get_verify_result(statePtr->ssl) != X509_V_OK) {
-		Tls_Error(statePtr, X509_verify_cert_error_string(SSL_get_verify_result(statePtr->ssl)));
+		Tls_Error(statePtr, (char *) X509_verify_cert_error_string(SSL_get_verify_result(statePtr->ssl)));
 	    }
 	    statePtr->flags |= TLS_TCL_HANDSHAKE_FAILED;
 	    *errorCodePtr = ECONNABORTED;
 	    return(-1);
 
@@ -367,11 +364,11 @@
 
 	case SSL_ERROR_SSL:
 	    /* A non-recoverable, fatal error in the SSL library occurred, usually a protocol error */
 	    dprintf("SSL error, indicating that the connection has been aborted");
 	    if (backingError != 0) {
-		Tls_Error(statePtr, ERR_reason_error_string(backingError));
+		Tls_Error(statePtr, (char *) ERR_reason_error_string(backingError));
 	    }
 	    *errorCodePtr = ECONNABORTED;
 	    bytesRead = -1;
 
 #if OPENSSL_VERSION_NUMBER >= 0x30000000L
@@ -385,11 +382,10 @@
 #endif
 	    break;
 
 	case SSL_ERROR_SYSCALL:
 	    /* Some non-recoverable, fatal I/O error occurred */
-
 	    if (backingError == 0 && bytesRead == 0) {
 		/* Unexpected EOF from the peer for OpenSSL 1.1 */
 		dprintf("(Unexpected) EOF reached")
 		*errorCodePtr = 0;
 		bytesRead = 0;
@@ -397,17 +393,17 @@
 
 	    } else if (backingError == 0 && bytesRead == -1) {
 		dprintf("I/O error occurred (errno = %lu)", (unsigned long) Tcl_GetErrno());
 		*errorCodePtr = Tcl_GetErrno();
 		bytesRead = -1;
-		Tls_Error(statePtr, Tcl_ErrnoMsg(Tcl_GetErrno()));
+		Tls_Error(statePtr, (char *) Tcl_ErrnoMsg(Tcl_GetErrno()));
 
 	    } else {
 		dprintf("I/O error occurred (backingError = %lu)", backingError);
 		*errorCodePtr = backingError;
 		bytesRead = -1;
-		Tls_Error(statePtr, ERR_reason_error_string(backingError));
+		Tls_Error(statePtr, (char *) ERR_reason_error_string(backingError));
 	    }
 	    break;
 
 	case SSL_ERROR_ZERO_RETURN:
 	    dprintf("Got SSL_ERROR_ZERO_RETURN, this means an EOF has been reached");
@@ -554,11 +550,10 @@
 	    Tls_Error(statePtr, "Peer has closed the connection for writing by sending the close_notify alert");
 	    break;
 
 	case SSL_ERROR_SYSCALL:
 	    /* Some non-recoverable, fatal I/O error occurred */
-
 	    if (backingError == 0 && written == 0) {
 		dprintf("EOF reached")
 		*errorCodePtr = 0;
 		written = 0;
 		Tls_Error(statePtr, "EOF reached");
@@ -565,25 +560,25 @@
 
 	    } else if (backingError == 0 && written == -1) {
 		dprintf("I/O error occurred (errno = %lu)", (unsigned long) Tcl_GetErrno());
 		*errorCodePtr = Tcl_GetErrno();
 		written = -1;
-		Tls_Error(statePtr, Tcl_ErrnoMsg(Tcl_GetErrno()));
+		Tls_Error(statePtr, (char *) Tcl_ErrnoMsg(Tcl_GetErrno()));
 
 	    } else {
 		dprintf("I/O error occurred (backingError = %lu)", backingError);
 		*errorCodePtr = backingError;
 		written = -1;
-		Tls_Error(statePtr, ERR_reason_error_string(backingError));
+		Tls_Error(statePtr, (char *) ERR_reason_error_string(backingError));
 	    }
 	    break;
 
 	case SSL_ERROR_SSL:
 	    /* A non-recoverable, fatal error in the SSL library occurred, usually a protocol error */
 	    dprintf("SSL error, indicating that the connection has been aborted");
 	    if (backingError != 0) {
-		Tls_Error(statePtr, ERR_reason_error_string(backingError));
+		Tls_Error(statePtr, (char *) ERR_reason_error_string(backingError));
 	    }
 	    *errorCodePtr = ECONNABORTED;
 	    written = -1;
 	    break;
 
@@ -946,8 +941,8 @@
     NULL,			/* Wide seek proc */
     NULL,			/* Thread action */
     NULL			/* Truncate */
 };
 
-Tcl_ChannelType *Tls_ChannelType(void) {
+const Tcl_ChannelType *Tls_ChannelType(void) {
     return &tlsChannelType;
 }