I just tried to compile package ntop-3.2-3 with a non standard version of
the GNU C compiler.

It said

1.

ssl.c:307: warning: `return' with no value, in function returning non-void

The source code is

int term_ssl_connection(int fd) {
  int i, rc;

  if(!myGlobals.sslInitialized) return;

Suggest add expression to return statement.

2.

fcUtils.c:657: warning: array subscript out of range

The source code is

    entry->alias[MAX_LEN_SYM_HOST_NAME] = '\0';

3.

graph.c:2638: warning: array subscript out of range

The source code is

  p[MAX_FC_DOMAINS+1] = 0;

4.

pbuf.c:3321: warning: array subscript out of range

The source code is

                    serverName[MAX_LEN_SYM_HOST_NAME-2] = '\0';