Errata

Despite our best efforts to avoid errors in the text, and sample applications that accompany Windows Sockets Network Programming, a few slipped by. Our apologies for any confusion or inconvenience that these might have caused. This page tries to make amends for our oversights. Also watch the descriptions of our sample applications for notes of any significant enhancements.

We would greatly appreciate hearing about any other errors, or points of confusion that you come across. Please mail them to us at rcq@sockets.com. If you don't see them here, then we don't know about them.

• On the Samples Disk The AS_ECHO directory mistakenly has AC_FTP32.DEF in place of ASECHO32.DEF
• Page 41, Figure 3-4:
  
• Class C Network Range should be 192.0.0.0 to 223.255.255.0 (note the trailing zero)
• Class D Network Range should be 224.0.0.0 to 239.255.255.255 (note the leading 224)
• Class D bit mask should be 1110 (note the trailing zero)
• Page 52, bottom: ends with "Unlike." The remander of this paragraph is missing:

Unlike the SOCK_STREAM or SOCK_DGRAM socket types, when you select the socket type SOCK_RAW there are no defaults. You must always specify the protocol value (as we describe in Chapter 16).

You can hardcode the value for the protocol parameter...

• The sockaddr structure length is not "always 4 for TCP/IP", but sizeof(struct sockaddr) (which is 16 bytes, but should not be hardcoded as such). This error appears in a number of places:
• Page 57, top, for namelen parameter
• Page 62, top, for namelen parameter
• Page 64, top, for addrlen parameter
• Page 67, middle, for tolen parameter
• Page 69, middle, for fromlen parameter
• Pages 68 and 69, middle: The description of the buf parameter for recv() and recvfrom() should say "pointer to buffer to receive data" (the current description--"pointer to buffer containing data to send," refers to the buf parameter for the send() and sendto() functions).
• Page 69: make it more clear that for UDP you cannot filter out incoming datagrams with recvfrom(), but you can by calling connect()

.

• Page 71: Figure 4-9 replace "used" with "uses" in caption
• Page 73: Heading "Connection-oriented (TCP) Network Applications should be bold with larger font like heading at top of page 74.
• Page 73: Under "Server" column, replace "struct" with "structure"
• Page 74, to bottom: "Also note: of course, a client or server can use either the connect()/send()/recv() or sendto()/recvfrom() regardless of what APIs the peer application uses to send and receive."
• Page 79: Font is different in last "Blocks until..." description
• Page 90, lines 13, 14, 15: "stRemAddr" should be "stDstAddr"
• Page 96, mid-page: "fd_read" should be "readfds"
• Page 96, bottom of page: insert "SOCKADDR_IN stDstAddr" line below "SOCKET s;" line
• Page 96, last two lines: change "stRemAddr" to "stDstAddr"
• Page 97, first line: change "stRemAddr" to "StDstAddr"
• Page 97, line 5: "WSAGetLastError" should have "()" after it
• Page 97: last 10 lines should be indented since they are within the for() loop
• Page 97 and 98: the check for "GetTickCount() > lGiveupTime" should be within both for loops, rather than in the for() conditional, since the "nWSAerror != 0" check after each loop will miss a timeout error otherwise.
• Page 102, mid-page: in description of hAsyncTaskHandle replace "canceled" with "cancelled" (for consistency).
• Page 103, mid-page: below "connect," "WSAGetLastError" should have "()" after it.
• Page 103, bottom:change "case (IDM_ASYNC)" to "CASE IDM_ASYNC:"
• Page 103, mid-page: add declaration of nBytesSent as int (next to nBytresXferred)
• Page 104, mid-page: add colons to FD_CONNECT, FD_WRITE, and FD_CLOSE case statements
• Page 104, mid-page: replace the FD_WRITE code with the following:

case FD_WRITE:

/* this event occurs when we're initially connected
* and subsequently whenever send() fails with an
* WSAEWOULDBLOCK error */
for (nBytesXferred=0; nBytesToXfer-nBytesXferred; ) {

nRet = send (s, /* send string */

(LPSTR)&(achOutBuf[nBytesXferred]),
nBytesToXfer - nBytesXferred,
0);

if (nRet == SOCKET_ERROR) {

if (WSAGetLastError() != WSAEWOULDBLOCK) {

<report error> /* fatal error */
<abort the connection>

}

break;

} else {

nBytesXferred += nRet; /* tally bytes sent */

}

}

/* if all bytes are sent, close the connection gracefully */
if ((nBytesToXfer - nBytesXferred) <= 0) {

<call shutdown (how=1)>
<loop on recv() until *any* error occurs>
<fall through to close the socket>

} else {

break;

}

case FD_CLOSE:

• Page 104, bottom: replace nBytesXferred referenced in FD_READ handler, with XBytesSent (which should be declared on page 103, along with nBytesXferred and nBytesToXfer)
• Page 106, mid-page: the "File" and "Open" menu selections should be italicized like the others.
• Page 107, line 33: replace "MAXHOST NAME" with "MAXHOST_NAME"
• Page 108, bottom: The assignment to wndclass.hIcon should be wndclass.hIcon = LoadIcon(hInst, MAKEINTRESOURCE(AU_TIME));
• Page 132, bottom: The MSG_OOB flag should only have one asterisk, rather than two.
• Page 132: In table 6-4, "with" under "FD_OOB" should be moved to the right with the "ready to read" text so the extra line is removed
• Page 145, line 23: szHost_name and MAXHOST_NAME need underscores added
• Page 146, 2/3 page: remove "MSG msg;"
• Page 146: Add declaration of hInstance and stWSAData even though they are defined externally in WinSockx.
• Page 147, line 13: replace "return msg.wParam" with "return(0);"
• Page 151, line 35: remove embedded space in "gethostname"
• Page 151, line 35: add underscore to MAXHOST_NAME
• Page 151, line 38: add underscore to both szHost_name
• Page 155, middle: The calculation of what's left to send should be:
  cbLeftToSend = cbTotalToSend - cbTotalSent;
• Page 208, screen shot: The Application Options dialog box should be replaced by the Filename dialog box used throughout our FTP client application to prompt for filenames and directories.
• Page 210, screen shot: This screen shot incorrectly shows the Error dialog box, but should show the Application Options dialog box that appears on page 208.
• Page 213, bottom: replace (LPSTR)szFtpCmd with (LPSTR)&(szFtpCmd[nBytesSent])
• Page 224, middle: replace if (hDataSock == SOCKET_ERROR) with if (hDataSock == INVALID_SOCKET). The sample source code also had this error, but since the values for the manifest constants are the same (-1), the resulting binaries are unaffected
• Page 241, 1ine 5: Change "GetBuf()" to "GetAddr()"
• Page 264, middle: replace lpWSAHostent->h_addr; with *(u_long FAR *)lpWSAHostent->h_addr; since each entry in the h_addr_list array is a pointer to an IP address, not an IP address itself.
• Page 261, bottom: gethostbyname() name argument should be const char FAR *
• Page 264, bottom: WSAAsyncGetHostByName() name argument should be const char FAR *
• Page 269, bottom: gethostbyaddr() addr argument should be const char FAR *
• Page 270, middle: Swap arguments in gethostbyaddr() "AF_INET" and "sizeof(struct in_addr)" (e.g. AF_INET is 2nd argument, and length is 3rd)
• Page 270, bottom: WSAAsyncGetHostByAddr() addr argument should be const char FAR *
• Page 272, middle: WSAAsynchGetHostByName() should be WSAAsyncGetHostByAddr()
• Page 292, bottom: Change &stLinger to &bOptVal
• Page 315, bottom: last parameter for getsockname() sample should be a pointer to an integer. Oddly, this parameter is just for output of the length, rather than both input and output as one would think, since the application is providing the buffer in the second input argument.
• Page 317, bottom: last parameter for getpeername() sample should be a pointer to an integer (same problem() and ambiguity as getsockname() has on page 315)
• Page 323, top: iMaxSockets and iMaxUdpDg should be u_short (not long)
• Page 327, bottom: replace .both occurances of ".wHighestVersion" with ".wHighVersion"
• Page 327, bottom: replace "HIWORD" with "HIBYTE", and "LOWORD" and "LOBYTE"
• Page 333, middle: getservbyname() name and proto argument should be const char FAR *
• Page 334, bottom: WSAAsyncGetServByName() name and proto arguments should be const char FAR *
• Page 338, middle: getservbyport() proto argument should be const char FAR *
• Page 339, middle: WSAAsyncGetServByPort() proto argument should be const char FAR *
• Page 343, middle: getprotobyname() name argument should be const char FAR *
• Page 343, middle: WSAAsyncGetProtoByName() name argument should be const char FAR *
• Page 435, line 27: replace "(long)" with "(int)"
• Page 435: replace code beginning at line 24 with the following (the changes represent a reorganization of existing code, to handle the message data in a different location in the code):
  
  

} else {


if (nAppState & STATE_GETTING_LENGTH) {


nDataLen += nDataRecvd;
if (nDataLen >= DATALEN) { /* we got the data length */


nDataToRead = ((int)*(achDataIn))-DATALEN-nDataRecvd;
nAppState = STATE_GETTING_DATA;
nDataLen = 0;


} else {


nDataToRead -= nDataRecvd; /* update bytes to read */


}

} else if (nAppState & STATE_GETTING_DATA) {


nDataToRead -= nDataRecvd; /* update bytes to read */


}

if (nDataToRead <= 0) { /* we got it all! */


nDataToRead = MINDATASIZE + DATALEN; /* reset things */
nAppState = STATE_GETTING_LENGTH;
lpDataIn = (char FAR *)achDataIn;



}


}


• Page 440: Add asterisk to "Good News Code", and a footnote to the bottom of the page that says "Micheal S. Greenberg deserves credit for originating the concept of "Good News Code"
• Page 475, bottom: The ip_hl and ip_v fields in the ip_hdr structure (IP Header Length, and IP version, respectively) should be reversed, and each should be 4 bits in size, not a full byte.
• Page 487, 5th line: replace "all-hosts address" with "group address".
• Page 489, bottom: In the call to setsockopt(), the option name should be IP_MULTICAST_TTL (not IP_MULTICAST_LOOP).
• Page 489, middle and bottom: interesting issue raised by an alert reader: I used sizeof(int) for IP_MULTICAST_LOOP and IP_MULTICAST_TTL option values, although Steve Deering's original document describing the sockets multicast API, "IP Multicast Extensions for 4.3BSD and Related Systems," used sizeof(char) and sizeof(u_char), respectively. It is true that the Time-To-Live value is only 8-bits in size in the IP header, but the analogous IP_TTL socket option uses sizeof(int). Regardless of that seeming contradiction, since Microsoft uses sizeof(int) for both in their multicast support, and the TCP/IP section of the WinSock 2 Protocol-Specific Annex also references sizeof(int), I will continue to do so also. My apologies for the confusion
• Page 490, middle: "stIpMreq.imr_multiaddr.s_addr = DESTINATION_MCAST" should be "stIpMreq.imr_multiaddr.s_addr = inet_addr (DESTINATION_MCAST)"
• Page 489, middle: "nOptVal" should be "&nOptVal" (i.e. address of)
• Page 498, bottom: in the 4th printing and later, WSALookupServiceBegin() next to WSAAsyncSelect() should be WSAEventSelect().
• Page 534,middle: The TCP acknowledgement value in segment 4 should be 0x013c1c0b (the 'b' is missing). Also (less significant), the "0x" designation is missing in the TCP sequence number, and leading zero is missing in segment 6.
• Page 611: remove www.lcs.com, and the blank line afer it

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Last updated 10/02/98 by Bob Quinn