Socket Error Code List

最近在Coding有關TCP/IP 的程式時, 當然免不了, 會有不預期的ErrorCode產生。就最常發生的ErrorCode, 我找了一些相關資料彙整如下: (提供給有需要的人..^^ 包含我自已 參考！)
Error return codes list and meaning.
WSAEINTR 10004
WSAEBADF 10009
WSAEACCES 10013
WSAEFAULT 10014
WSAEINVAL 10022
WSAEMFILE 10024
WSAEWOULDBLOCK 10035
WSAEINPROGRESS 10036
WSAEALREADY 10037
WSAENOTSOCK 10038
WSAEDESTADDRREQ 10039
WSAEMSGSIZE 10040
WSAEPROTOTYPE 10041
WSAENOPROTOOPT 10042
WSAEPROTONOSUPPORT 10043
WSAESOCKTNOSUPPORT 10044
WSAEOPNOTSUPP 10045
WSAEPFNOSUPPORT 10046
WSAEAFNOSUPPORT 10047
WSAEADDRINUSE 10048
WSAEADDRNOTAVAIL 10049
WSAENETDOWN 10050
WSAENETUNREACH 10051
WSAENETRESET 10052
WSAECONNABORTED 10053

WSAECONNRESET 10054
WSAENOBUFS 10055
WSAEISCONN 10056
WSAENOTCONN 10057
WSAESHUTDOWN 10058
WSAETOOMANYREFS 10059
WSAETIMEDOUT 10060
WSAECONNREFUSED 10061
WSAELOOP 10062
WSAENAMETOOLONG 10063
WSAEHOSTDOWN 10064
WSAEHOSTUNREACH 10065
WSAENOTEMPTY 10066
WSAEPROCLIM 10067
WSAEUSERS 10068
WSAEDQUOT 10069
WSAESTALE 10070
WSAEREMOTE 10071
WSAEDISCON 10101
The following is a list of possible error codes returned by
WorldCast, along with their extended explanations.
Errors are listed in alphabetical order by error macro.

WSAEINTR (10004) 被中斷的系統呼叫
Interrupted function call.
A blocking operation was interrupted by a call to WSACancelBlockingCall.
當以阻攔式進行的WinSock函式被WSACancelBlockingCall()中斷的時候，這個阻攔式函式會得到WSAEINTR這個錯誤訊息。讀者要注意的是，當你的程式有用WSACancelBlockingCall去中斷阻攔式函式的時候，你必須為這個阻攔式函式寫處理WSAEINTR錯誤訊息的程式碼，否則你的程式可能會出現些無預期的錯誤。

原則上，所有能以阻攔式進行的函式都可能會發生這個錯誤。


WSAEBADF (10009) 錯誤的檔案代碼
Bad file handle. This error means that the supplied file handle is invalid. Under Microsoft Windows CE, it is possible for the socket function to return this error, which indicates that the shared serial port is busy.
柏克萊socket介面中，檔案描述子和socket描述子是相通的，開啟socket可以想像成開啟一個檔案。WSAEBADF在柏克萊socket介面的意義是指錯誤的socket描述子，這個錯誤的socket描述子可能是未經開啟的socket或是以關閉的socket。

在WinSock中有個相通的錯誤代碼WSAENOTSOCK，用來指定錯誤的socket描述子。詳細說明請參考WSAENOTSOCK部分。


WSAEACCES (10013) 無此權限
Permission denied. An attempt was made to manipulate the socket, which is forbidden. This error most commonly occurs when attempting to use a broadcast address in sendto or WSASendTo, in which broadcast permission has not been set with setsockopt and the SO_BROADCAST option.

對於柏克萊socket介面函式，這個錯誤發生的原因通常是開啟一個不具有開啟權限的檔案或socket。例如在UNIX上，一般的使用者不能開啟 SOCK_RAW的socket，通常是超級使用者(super user)才有此權限。如果一般的使用者企圖開啟SOCK_RAW的socket，將會得到這個錯誤訊息。

對於WinSock API函式介面，發生此錯誤的函式有二：send()和sendto()。當利用send()或sendto()傳送資料的時候，將目的位址設成廣播位址 ( broadcast address )，但是並未呼叫setsockopt()設定SO_BROADCAST選項時便會發生WSAEACCES錯誤。


WSAEFAULT (10014) 錯誤的記憶體位址
Invalid address. The pointer address passed into the Winsock function is invalid. This error is also generated when the specified buffer is too small.
系統偵測出使用錯誤的記憶體位址。呼叫WinSock函式時，常常會有參數是以指標的方式傳入，這個指標可能是指向一個結構，如sockaddr_in結構，或是指向一個資料緩衝區。當程式不小心傳入一個錯誤記憶體未指的指標時，就會發生WSAEFAULT這個錯誤。此外，當指標所指向的記憶體區塊太小的時候，也會發生這個錯誤。


WSAEINVAL (10022) 參數錯誤
Invalid argument. An invalid argument was specified. For example, specifying an invalid control code to WSAIoctl generates this error. This code can also indicate an error with the current state of a socket—for example, calling accept or WSAAccept on a socket that is not listening.

如果傳入不正確的參數給WinSock函式的話，會導致WSAEINVAL這個錯誤。如果參數是一個結構的指標，此結構內容填入不正確的值，也會導致這個錯誤。例如，shutdown()函式的how()參數只能是0、1或2，若是設定成其他數值，就會出現這個錯誤。在網路程式的設計中，函式和函式之間的呼叫通常有一定的順序，如過不照這個順序進行，也會出現這個錯誤。底下是針對每個相關函式的詳細說明。

函式
錯誤發生的時機
----------------------------------------------------------->>>
accept() 呼叫accept()之前沒有成功呼叫listen() bind() 已經成功呼叫bind()函式而指定stocket的名稱了 getstockname() 沒有呼叫bind()函式指定socket名稱 listen() 已經處於連接狀態或是socket沒有呼叫bind()函式指定socket名稱 recv()和recvfrom() 對於datagram socket，socket沒有呼叫bind()函式指定IP位址、port和協定等；對於stream socket，連接尚未建立 send()和sendto() 對於datagram socket，socket沒有呼叫bind()函式指定IP位址、port和協定等；對於stream socket，連接尚未建立
<<<-----------------------------------------------------------
原則上，所有函式其參數所能設定的值有一定的範圍，或是有一些特定的值，這些函式都有可能發生這個錯誤。


WSAEMFILE (10024) 太多開啟的檔案
Too many open files. Too many sockets are open. Typically, Microsoft providers are limited only by the amount of resources available on the system.
柏克萊socket介面的解釋是開啟過多的檔案，超過檔案開啟數的限制。在柏克萊socket將檔案和socket的開啟以檔案描述子(file deforbiddenor)描述。WinSock對於socket是有別於檔案的，WSAEMFILE在WinSock的意義是開啟太多的 socket。

這個程式通常發生在同一部機器中執行過多的網路程式，以致開啟過多的socket。另一種可以避免的錯誤是應用程式沒有正常的關閉不用的socket，以致socket資源耗盡。

WSAEWOULDBLOCK (10035) 函式作用阻攔中
Resource temporarily unavailable. This error is most commonly returned on nonblocking sockets in which the requested operation cannot complete immediately. For example, calling connect on a nonblocking socket returns this error because the connection request cannot be completed immediately.

當函式作用是以非阻攔式進行，而此刻的函式作用再返回時其函式作用尚未完成的時候，就會出現這個錯誤。舉例來說，假設send()以非阻攔式傳送一段資料至遠端主機，假設函式返回時得到WSAEWOULDBLOCK這個錯誤，這樣表示這一段資料不能在這一次的send()函式呼叫中傳送完。

對於connect()函式，這個錯誤表示尚未成功地連接上遠端主機，連接要求正在進行中。若你的程式中有利用setsockopt()函式以SO_LINGER設定時限，在呼叫closesocket()時有可能出現這個錯誤。

對於非同步的網路資料函式( WSAAsyncGetXXXXByYYYY())而言，得到WSAEWOULDBLOCK錯誤，表示要查詢的網路資料目前無法取得。這通常是個暫時性的錯誤，應用程式可能稍後再呼叫相同的函式就會成功。


WSAEINPROGRESS (10036) 有阻攔函式正在執行中
Operation now in progress. A blocking operation is currently executing. Typically, you do not see this error unless you are developing 16-bit Winsock applications.

對於每個process或thread，WinSock只允許”一”個阻攔式函式的執行。如果已有阻攔式函式正在執行，而又呼叫到WinSock函式，函式會傳回WSAEINPROGRESS的錯誤。

這個錯誤也會發生在需要長執行時間的函式，如connect()。有一種情況是這樣：當執行”非阻攔式”的connect()函式兩次，由於是非阻攔式的 connect()，第一次的呼叫傳回WSAEWOULDBLOCK錯誤碼。此時要求連接動作尚未完成，第二次的connect()呼叫就會得到 WSAEINPROGRESS的錯誤。

我們的建議是在有可能發生這種錯誤的函式呼叫前加上WSAIsBlocking()判斷是否有阻攔式函式正在執行。如果有的話，我們可能需要將正在進行的阻攔式函式取消掉，或是將目前想要做的事取消掉。


WSAEALREADY (10037) 函式作用已完成
Operation already in progress. This error typically occurs when an operation that is already in progress is attempted on a nonblocking socket—for example, calling connect or WSAConnect a second time on a nonblocking socket already in the process of connecting. This error can also occur when a service provider is in the process of executing a callback function (for those Winsock functions that support callback routines).

這個錯誤的意思在柏克萊socket介面和WinSock函式的解釋上有很大的差別。柏克萊socket介面的解釋是函式作用已完成；在WinSock 中，WSAEALREADY的意思是：”你想要取消的非同步事件已經被取消了！”，也就是當你呼叫WSACancelAsyncRequest()試圖去取消一個非同步事件時，而該事件已被取消了。


WSAENOTSOCK (10038) 非法的socket
Socket operation on an invalid socket. This error can be returned from any Winsock function that takes a SOCKET handle as a parameter. This error indicates that the supplied socket handle is not valid.
通常WinSock函式都要以socket描述子當參數傳入，如果這個socket描述子所代表的socket不是正確開啟的或是根本沒有開啟，函式就會得到WSAENOTSOCK錯誤。原則上，只要以socket描述子當參數傳入的函式都有發生WSAENOSOCK錯誤的可能。
WSAEDESTADDRREQ (10039) 需要對方位址
Destination address required. This error indicates that the supplied address was omitted. For instance, calling sendto with the destination address INADDR_ANY returns this error.
當你要傳送資料給遠端機器，必須指定對方的位址(和port等等)，才能正確送達。檢查看看你的應用程式是否在呼叫connect()或sendto()時，正確地填入對方的sockaddr結構。


WSAEMSGSIZE (10040) 訊息太長，緩衝區無法容納
Message too long. This error can mean a number of things. If a message is sent on a datagram socket that is too large for the internal buffer, this error occurs. It also occurs if the message is too large because of a network limitation. Finally, if on receiving a datagram the buffer is too small to receive the message, this error is generated.
這個錯誤發生原因是由於訊息資料過大，緩衝區無法容納，這裡的緩衝區可能是使用者指定的或是系統內部用的緩衝區。會發生這個錯誤的函式有四:

函式
錯誤發生的時機
--------------------------------->>>
recv()、recvform() 利用datagram socket接收資料時，如果recv()、recvform()指定的緩衝區長度小於接收進來datagram，這時後過長的datagram會被丟棄並告訴函式WSAEMSGSIZE這個錯誤 send()、sendto() 利用datagram socket傳送資料時，如果送出的資料緩衝區大於WinSock所能傳遞datagram的最大長度，這時send()和sendto()傳回發生WSAEMSGSIZ這個錯誤訊息
<<<--------------------------------- WSAEPROTOTYPE (10041) 錯誤的協定型別
Wrong protocol type for socket. A protocol was specified in a call to socket or WSASocket that does not support the semantics of the given socket type. For example, requesting the creation of an IP socket of type SOCK_STREAM and protocol IPPROTO_UDP generates this error.

錯誤產生的原因是在socket()函式呼叫時指定了WinSock不支援的協定舉例來說，你不可以在steam socket(SOCK_STREAM)設定以UDP協定傳輸(IPPRO_UDP)。 stream socket並不支援UDP通訊協定。如果你真的有心去測試的話，程式中故意如此呼叫socket():hSock=socket(AF_INET， SOCK_STREAM， IPPROTO_UDP);你會發現，這樣的socket()函式呼叫會得到WSAEPROTONOSUPPORT錯誤。這顯然不對，照理應該得到 WSAEPROTOTYPE這個錯誤才對。WSAEPROTOTYPE這個錯誤表示指定了錯誤的協定，而所指定的協定是該位址家族(協定家族)所支援的，但不適用於socket型別。以上述的例子來看，UDP協定是屬於AF_INET這個位址家族，但是並不能用於stream socket(SOCK_STREAM socket)上。WSAEPROTONOSUPPORT這個錯誤表示所指定的協定是該協定家族所不支援的，意思上和WSAEPROTOTYPE有點出入。

事實上，WSAEPROTOTYPE和WSAEPROTONOSUPPORT之間的差別是微乎其微的。在發展網路程式的時候，這兩種錯誤都是代表著同一種狀況--協定指定錯誤。

總之，你永遠也沒辦法試出WSAEPROTOTYPE這個錯誤。


WSAENOPROTOOPT (10042) 錯誤的協定選項(option)
Bad protocol option. An unknown, unsupported, or invalid socket option or level was specified in a call to getsockopt or setsockopt.
這個錯誤主要是針對getsockopt()和setsockopt()函式的。這兩個函式可以以參數設定不同的選項而有不同的作用。對於每個選項多多少少會有些限制，如有些選項只能用在stream socket，而有些只能用在datagram socket。如果違反這些限制，就會發生這個錯誤。請看下表:

SO_DONTLINGER SO_KEEPALIVE SO_LINGER SO_OOBINLINE TCP_NODELAY
datagram socket ( SOCK_DGRAM )不支援這些選項

SO_DEBUG SO_DONTROUTE SO_RCVBUF SO_SNDBUF TCP_NODELAY
有些廠商的WinSock TCP/IP協定核心不支援這些選項

SO_ACCEPTCONN SO_ERROR SO_TYPE
這些選項只適用於getsockopt()函式，不能作用於setsockopt()函式


WSAEPROTONOSUPPORT (10043) 不支援的協定
Protocol not supported. Either the requested protocol is not installed on the system or no implementation exists for it. For example, if TCP/IP is not installed on the system, attempting to create either a TCP or UDP socket generates this error.
WinSock協定核心不支援所指定的通訊協定。舉例來說當你用socket()函式時，第二個參數指定為SOCK_STREAM，第三個參數指定為 IPPROTO_ICMP，如此socket()呼叫會得到WSAEPROTONOSUPPORT這個錯誤。WinSock 1。1版並不支援ICMP協定，所以呼叫socket()指定ICMP這個協定，就會發生錯誤。事實上，產生WSAEPROTONPSUPPORT錯誤的狀況不只這樣，詳見WSAEPROTOTYPE。









WSAEADDRINUSE (10048) 位址已被指定了
Address already in use. Under normal circumstances, only one socket is permitted to use each socket address. (For example, an IP socket address consists of the local IP address and port number.) This error is usually associated with the bind, connect, and WSAConnect functions. The socket option SO_REUSEADDR can be set with the setsockopt function to allow multiple sockets access to the same local IP address and port. (For more information, see Chapter 7.)

所指定的”位址”正在使用中。這裡的位址是指socket的名稱，包含三部分：協定、port和IP位址。這個錯誤發生的原因通常是應用程式試圖利用 bind()函式去指定port時，此port已被其他應用程式所佔用了。這種情況發生於在同一部主機上執行兩個相同性質(指定相同socket名稱)的 server程式，第二的程式會因為第一個程式先佔用某個port而得到此錯誤訊息。

還有一種常見的情況就是在撰寫client程式時，利用bind()去指定socket的port，此舉常會有這個錯誤發生。並非不能用bind()去指定socket的port，而是你無法確定程式執行的時候，所指定的port是否有其他程式正在使用。通常很少會在client程式中呼叫bind()函式，一般的client程式都是讓系統幫你選一個適當的port。

此外，應用程式可以利用setsockopt()的SO_REUSEADDR選項，允許port可以重複使用，可是我們並不鼓勵這樣做。這樣可能會造成TCP/IP核心在判斷應用程式上的困擾。


WSAEADDRNOTAVAIL (10049) 無法指定位址
Cannot assign requested address. This error occurs when the address specified in an API call is not valid for that function. For example, specifying an IP address in bind that does not correspond to a local IP interface generates this error. This error can also occur when specifying port 0 for the remote machine to connect to with connect, WSAConnect, sendto, WSASendTo, and WSAJoinLeaf.

錯誤發生的原因通常是指定了該部機器不應該有的位址。這裡的位址包含三個部分：網路協定、port和IP位址。

在柏克萊socket介面中，呼叫bind()時，若指定的IP位址不是本地機器該有的位址，就會出現這個錯誤。在呼叫connect()或 sendto()函式時，如果sockaddr_in結構中的sin_port填”0”，如此也會導致這個錯誤(在UNXI上是 EADDRNOTAVAIL錯誤)。

對於WinSock函式，錯誤發生的時機和柏克萊socket函式類似，bind()和connect()都會導致這樣的錯誤。
對於WinSock函式，錯誤發生的時機和柏克萊socket函式類似,bind()和connect()都會導致這樣的錯誤。WinSock 1.1 版的規格書中並沒有提到bind()函式會導致WSAEADDRNOTAVAIL錯誤，不過根據我們測試的結果，bind()也會導致這樣的錯誤。


WSAENETDOWN (10050) 網路出錯
Network is down. The operation encountered a dead network. This could indicate the failure of the network stack, the network interface, or the local network.
下層的網路系統發生問題，WinSock函式無法執行。這是一個相當嚴重的問題，這會使得幾乎所有的WinSock函式呼叫失敗。若你的WinSock函式發生錯誤，那麼請你該好好地檢查你的網路卡，網路卡驅動程式和你的WinSock協定核心。


WSAENETUNREACH (10051) 無法連上指定的網路
Network is unreachable. An operation was attempted to an unreachable network. This indicates that the local host does not know how to reach the remote host—in other words, no known route to the destination exists.
在柏克萊socket介面中，這個錯誤的意思是無法和對方網路系統取得聯繫。在WinSock 1。1規格中，WSAENETUNREACH相通於柏克萊socket介面中的ETHOSTUNREACH。


WSAENETRESET (10052) 網路已被重新設定
Network dropped the connection on reset. The connection has been broken because keepalives have detected a failure. This error can also occur when attempting to set the SO_KEEPALIVE option with setsockopt on a connection that has already failed.

對方主機出錯而重新開機。在本地主機呼叫和傳送資料有關的函式就會得到這個錯誤。對於setsockopt()函式，這個錯誤發生的原因在於試圖設定SO_KEEPALIVE於逾時(timeout)的連接。


WSAECONNABORTED (10053) 中斷連接
Software caused the connection to abort. An established connection was aborted due to a software error. Typically, this means the connection was aborted due to a protocol or timeout error.

在連接建立後，當有某種原因導致TCP/IP協定核心不斷地重送資料，而且都重送失敗的時候，TCP/IP協定將連接中斷。此時，應用程式就會收到WSACONNABORTED這個錯誤。


WSAECONNRESET (10054) 連結已被對方重新設定
Connection reset by peer. The remote host forcibly closed an established connection. This error can occur if the remote process is abnormally terminated (as in memory violation or hardware failure) or if a hard close was performed on the socket. A socket can be configured for a hard close using the SO_LINGER socket option and setsockopt. (For more information, see Chapter 7.)

連結已被對方系統強迫中斷了。TCP/IP協定核心如果偵測出stream socket的連接發生問題的話，它會傳一個表示連接重設(reset)的訊息給對方。此時對方程式會得到WSAECONNRESET的錯誤訊息。


WSAENOBUFS (10055) 緩衝區過小
No buffer space available. The requested operation could not be performed because the system lacked sufficient buffer space.

WinSock核心無法配置足夠的緩衝區，無法執行該程式。這個錯誤的發生和整個Windows系統資源有關。如果整個Windows本身可用的資源就很少，所能同時執行的程式也少。也有可能是執行了"不良"的應用程式，沒有正常的使用和歸還系統資源(如記憶體)。或是某些應用程式的不正常關閉，也會佔用系統資源。


WSAEISCONN (10056) socket已經連接
Socket is already connected. A connection is being attempted on a socket that is already connected. This can occur on both datagram and stream sockets. When using datagram sockets, if connect or WSAConnect has been called to associate an endpoint's address for datagram communication, attempting to call either sendto or WSASendTo generates this error.

網路函式通常會有一定的呼叫順序，有的函式呼叫成功後便不能再呼叫，否則會出現錯誤。當連接建立時，client程式呼叫()成功，而server程式呼叫accept()成功。此時若client程式再呼叫一次connect()函式的話，會得到WSAEISCONN這個錯誤，表示該socket已經處於連接狀態了。如果client程式呼叫listen()函式的話也會出現這個錯誤，表示不應該在此時呼叫這個函式。對於server程式，如果 socket已經處於連接狀態，程式呼叫connect()函式的話，也會得到WSAEISCONN這個錯誤。

上述錯誤是發生在stream socket上，因為stream socket才會建立連接。對於datagram socket，多次成功的connect()函式呼叫是被允許的(對於datdgram socket而言，呼叫connect()函式的目的不在於建立連接)。datagram socket發生此錯誤的原因是在sendto()函式上，當呼叫sendto()傳送datagram時，如果對方位址填入 INADDR_ANY(“0.0.0.0”)而port填入0(在sockaddr_in結構中)，就會導致WSAEISCONN這個錯誤。


WSAENOTCONN (10057) socket 尚未連接
Socket is not connected. This error occurs when a request is made to send or receive data on a connection-oriented socket that is not currently connected.

網路函式通常會有一定的呼叫順序，有些函式必須先呼叫成功某函式才能呼叫。WSAENOTCONN這個錯誤發生的原因很明顯，就是在連接建立之前，你試圖從連接對方取得資料或是傳送資料到對方，就會發生WSAENETCONN這個錯誤。

舉例來說，對於stream socket，如果在建立連結前呼叫send()試圖傳送資料，或者是呼叫recv()試圖取得資料，就會發生這個錯誤，告訴你socket尚未建立連接。你如果呼叫了getpeername()這個函式試圖去取得連接對方的socket，當然也會出現這個錯誤。對於setsockopt()這個函式，如果設定SO_KEEPALIVE，但連接已被中斷的話，也會出現WSAENETCONN這個錯誤。

初學者可能在呼叫connect()函式之後沒有檢查是否函式呼叫錯誤，以致不知道是否連接已正確建立。


WSAESHUTDOWN (10058) socket已經關閉
Cannot send after socket shutdown. The socket has already been partially closed by a call to shutdown, and either a send or a receive operation is being requested. Note that this occurs only on the data-flow direction that has been shut down. For example, after calling shutdown on sends, any call to send data generates this error.

這個錯誤碼的意思是，無法再傳送資料了，因為socket已經經由shutdown()函式而關閉了。當你利用shutdown()關閉socket之後，WinSock的TCP/IP協定核心就會關閉這個socket的傳送或接收的功能。有一點要注意的是，這個錯誤只會在stream socket出現。


WSAETOOMANYREFS (10059) 參照(reference)太多，資源耗盡
在UNIX作業系統中的解釋是指系統核心資源消耗殆盡。不過在WinSock 1.1版的規格書中並沒有任何一個函式會發生這種錯誤。


WSAETIMEDOUT (10060) 連接逾時(timeout)
Connection timed out. This error occurs when a connection request has been made and the remote computer fails to properly respond (or doesn't respond at all) after a specified length of time. This error is typically seen when the socket options SO_SNDTIMEO and SO_RCVTIMEO are set on a socket as well as when the connect and WSAConnect functions are called. For more information on setting SO_SNDTIMEO and SO_RCVTIMEO on a socket, see Chapter 7.

當程式試圖利用connect()連接一台遠端主機時，此主機一直沒有回應，經過了一段時間後，TCP/IP協定核心便會傳回connect()函式 WSAETIMEDOUT這個錯誤訊息。發生這個錯誤的原因可能是程式所要連接的遠端主機的系統發生問題，或者根本沒有這一台主機。也有一種可能的原因是本地機器的網路系統出現問題，導致本地主機無法正常與遠端主機聯繫。檢查你的網路系統的設定，看看有什麼不當的地方，如閘道器(gateway)的設定，主機名稱表(hosts)內主機名稱和網路位址的對照有錯誤等等。


WSAECONNREFUSED (10061) 連接受拒
Connection refused. The connection could not be established because the target machine refused it. This error usually occurs because no application on the remote machine is servicing connections on that address.

連接要求受到對方機器的回絕，無法和對方建立連接。這個錯誤並不是網路系統出了問題，而是對方機器的server程式拒絕client程式的連接要求，或者是根本沒有這個server程式存在。當TCP/IP核心收到某個連接要求時，會查看系統中是否有某server程式所監聽的port正好是這個連接要求所要連接的port，如果沒有此server程式，TCP/IP核心會回絕一個WSAECONNREFUSED給對方程式。

通常發生這個錯誤的原因有幾個。使用者可能連接到錯誤的遠端主機或是錯誤的port，也有可能是遠端主機和port對了，但是server程式並沒有執行。檢查看看程式中的sockaddr_in結構有沒有填錯? sockaddr_in中的IP位址和port是不是以網路位元組順序排列。


WSAELOOP (10062) 太多層的符號式鏈結(Symbolic link)
在UNIX作業系統中，這個錯誤的意思是指路徑參考過多的符號式鏈結(symbolic link)。


WSAENAMETOOLONG (10063) 檔名過長
在UNIX作業系統，這個錯誤的意思是指欲開啟檔案的路徑名稱(包括檔案名稱)太長。


WSAEHOSTDOWN (10064) 對方主機關閉
Host is down. This error indicates that the operation has failed because the destination host is down; however, an application is more likely to receive the error WSAETIMEDOUT because it typically occurs when attempting to establish a connection.

在柏克萊socket介面的解釋中，這個錯誤發生的原因是當遠端主機關閉或系統出問題。


WSAEHOSTUNREACH (10065) 無法聯繫對方主機
No route to host. An operation was attempted to an unreachable host. This error is similar to WSAENETUNREACH.

在柏克萊socket介面中，這個錯誤的意思是無法和對方主機取得聯繫。在WinSock方面，有類似的錯誤代碼，讀者可以參考WSAENETUNREACH這個錯誤的說明。


WSAEPROCLIM (10067) Too many processes.
Some Winsock service providers set a limit on the number of processes that can simultaneously access them.
A Windows Sockets implementation may have a limit on the number of applications that may use it simultaneously. WSAStartup() may fail with this error if the limit has been reached.


WSASYSNOTREADY (10091) 主機網路系統尚未備妥
Network subsystem is unavailable. This error is returned when calling WSAStartup, and the provider cannot function because the underlying system that provides services is unavailable.
本地主機的網路系統尚未能正常運作。若發生這個錯誤，讀者可能要檢查一下有沒有WINSOCK.DLL(或32位元版本的WSOCK32.DLL)這個檔案?這個檔存放的路徑正確嗎?


WSAVERNOTSUPPORTED (10092) 不支援的WinSock.DLL版本
Winsock.dll version out of range. The requested version of the Winsock provider is not supported.

錯誤發生的原因是在呼叫WSAStartup()函式時所指定的WinSock版本不被現有的WinSock版本所支援。若發生這個錯誤，讀者要確定一下本地Windows系統中的WinSock版本和該版本所能支援的版本是如何等等。通常較新的版本同時能支援新舊版本的WinSock，建議讀者能使用較新的WinSock版本。


WSANOTINITIALISED (10093) 未執行WSAStartup()
Winsock has not been initialized. A successful call to WSAStartup has not yet been performed.

應用程式沒有呼叫WSAStartup()或是呼叫WSAStartup()失敗。應用程式要成功地呼叫WSAStartup()才能使用WinSock.DLL，否則會有此錯誤訊息出現。


WSAEDISCON (10101) Graceful shutdown in progress.
Graceful shutdown in progress. WSARecv and WSARecvFrom return this error to indicate that the remote party has initiated a graceful shutdown. This error occurs on message-oriented protocols such as ATM.

Returned by WSARecv(), WSARecvFrom() to indicate the remote party has initiated a graceful shutdown sequence.


10102—WSAENOMORE
No more records found. WSALookupServiceNext returns this record to indicate that no additional records are left. This error is interchangeable with WSA_E_NO_MORE. Applications should check for both this error and WSA_E_NO_MORE.


10103—WSAECANCELLED
Operation canceled. This error indicates that a call to WSALookupServiceEnd was made while a call to WSALookupServiceNext was still processing. WSALookupServiceNext returns this error. This code is interchangeable with WSA_E_CANCELLED. Applications should check for both this error and WSA_E_CANCELLED.


10104—WSAEINVALIDPROCTABLE
The procedure call table is invalid. A service provider typically returns this error when the procedure table contains invalid entries. For more information on service providers, see Chapter 12.


10105—WSAEINVALIDPROVIDER
Invalid service provider. This error is associated with service providers, and it occurs when the provider cannot establish the correct Winsock version needed to function correctly.


10106—WSAEPROVIDERFAILEDINIT
The provider failed to initialize. This error is associated with service providers, and it is typically seen when the provider cannot load the necessary DLLs.


10107—WSASYSCALLFAILURE
(OS dependent) System call failure.
System call failure. A system call that should never fail has failed.

Returned when a system call that should never fail does. For example, if a call to WaitForMultipleObjects() fails or one of the registry APIs fails trying to manipulate the protocol/namespace catalogs.



10108—WSASERVICE_NOT_FOUND
No such service found. This error is normally associated with registration and name resolution functions when querying for services. (See Chapter 8 for more information about these functions.) This error indicates that the requested service could not be found in the given namespace.


WSATYPE_NOT_FOUND (10109)
Class type not found. This error is also associated with the registration and name resolution functions when manipulating service classes. When an instance of a service is registered, it must reference a service class that was previously installed with WSAInstallServiceClass.


10110—WSA_E_NO_MORE
No more records found. This error is returned from WSALookupServiceNext to indicate that no additional records are left. It is interchangeable with WSAENOMORE. Applications should check for both this error and WSAENOMORE.


10111—WSA_E_CANCELLED
Operation canceled. This error indicates that a call to WSALookupServiceEnd was made while a call to WSALookupServiceNext was still processing. WSALookupServiceNext returns this error. This code is interchangeable with WSAECANCELLED. Applications should check for both this error and WSAECANCELLED.


10112—WSAEREFUSED
Query refused. A database query failed because it was actively refused.


WSAHOST_NOT_FOUND (11001) 已經證實找不到主機
Host not found. This error occurs with gethostbyname and gethostbyaddr to indicate that an authoritative answer host was not found.

當你使用網路資料函式尋找主機的資料，而該主機不存在時，就會發生這個錯誤。尋找網路主機資料的方法通常是先尋找本地主機的網路名稱表(host檔)，如果找不到再透過DNS的途徑去找，如果再找不到，通常就會回給函式這樣的錯誤。

發生這樣的錯誤時，檢查看看本地主機的主機名稱解譯的設定有沒有問題。比較可能出現問題的是DNS的設定，確定是不是設定錯誤的DNS server。如果DNS server正確，確定一下DNS server有沒有跑起來。你可以利用ping這個程式看看DNS server有沒有跑起來，如果沒有ping這個程式，你可以試著去解釋一個確定存在的主機，看看DNS server有沒有在正常運作中。


WSATRY_AGAIN (11002) 找不到網路資料，但未被證實
Nonauthoritative host not found. This error is also associated with gethostbyname and gethostbyaddr, and it indicates that either the nonauthoritative host was not found or a server failure occurred.

這是一個暫時性的錯誤，告訴你目前找不到所要找的網路資料，你可以再試試看。


WSANO_RECOVERY (11003) 無法挽救的錯誤
A nonrecoverable error occurred. This error is also associated with gethostbyname and gethostbyaddr. It indicates that a nonrecoverable error has occurred and the operation should be tried again.

對於查詢主機名稱而言，這個錯誤發生的原因是由網域名稱系統(Domain Name System, DNS)所出現的錯誤所引起的。這些錯誤包括DNS的FORMERR、REFUSED和NOTIMP等錯誤，詳細請參考RFC1035有關網域名稱系統的文件。

對於查詢服務和協定資料而言，這個錯誤發生的原因是找不到存放網路資料的資料庫。這個資料庫通常是在本地主機上的檔案，如SERVICES和PROTOCOL這兩個檔。


WSANO_DATA (11004) 名稱合法，但查無此資料
No data record of the requested type found. This error is also associated with gethostbyname and gethostbyaddr. It indicates that the supplied name was valid but no data record of the requested type was found with it.

查詢格式是正確的，但是查無此資料存在。這通常是暫時性的錯誤，可能在不同的網路資料伺服器中能找到這份資料。


11005—WSA_QOS_RECEIVERS
At least one reserve message has arrived. This value is associated with IP Quality of Service (QOS) and is not an error per se. (See Chapter 10 for more on QOS.) It indicates that at least one process on the network is interested in receiving QOS traffic.


11006—WSA_QOS_SENDERS
At least one path message has arrived. This value is associated with QOS and is more of a status message. This value indicates that at least one process on the network is interested in sending QOS traffic.


11007—WSA_QOS_NO_SENDERS
No QOS senders. This value is associated with QOS and indicates that there are no longer any processes interested in sending QOS data. See Chapter 10 for a more complete description of when this error occurs.


11008—WSA_QOS_NO_RECEIVERS
No QOS receivers. This value is associated with QOS and indicates that there are no longer any processes interested in receiving QOS data. See Chapter 10 for a more complete description of this error.


11009—WSA_QOS_REQUEST_CONFIRMED
Reservation request has been confirmed. QOS applications can request that they be notified when their reservation request for network bandwidth has been approved. When such a request is made, this is the message generated. See Chapter 10 for a more complete description.


11010—WSA_QOS_ADMISSION_FAILURE
Error due to lack of resources. Insufficient resources were available to satisfy the QOS bandwidth request.


11011—WSA_QOS_POLICY_FAILURE
Invalid credentials. Either the user did not possess the correct privileges or the supplied credentials were invalid when making a QOS reservation request.


11012—WSA_QOS_BAD_STYLE
Unknown or conflicting style. QOS applications can establish different filter styles for a given session. This error indicates either unknown or conflicting style types. See Chapter 10 for a description of filter styles.


11013—WSA_QOS_BAD_OBJECT
Invalid FILTERSPEC structure or provider-specific object. This error occurs if either the FLOWSPEC structures or the provider-specific buffers of a QOS object are invalid. See Chapter 10 for more details.


11014—WSA_QOS_TRAFFIC_CTRL_ERROR
Problem with a FLOWSPEC. This error occurs if the traffic control component has a problem with the supplied FLOWSPEC parameters that are passed as a member of a QOS object.


11015—WSA_QOS_GENERIC_ERROR
General QOS error. This is a catch-all error that is returned when the other QOS errors do not apply.


6—WSA_INVALID_HANDLE
(OS dependent) Specified event object handle is invalid.
Specified event object invalid. This Windows error is seen when using Winsock functions that map to Win32 functions. This particular error occurs when a handle passed to WSAWaitForMultipleEvents is invalid.

An application attempts to use an event object, but the specified handle is not valid.


8—WSA_NOT_ENOUGH_MEMORY
(OS dependent) Insufficient memory available.
Insufficient memory available. This Windows error indicates that insufficient memory is available to complete the operation.

An application used a WinSock function which directly maps to a Win32 function. The Win32 function is indicating a lack of required memory resources.7


87—WSA_INVALID_PARAMETER
(OS dependent) One or more parameters are invalid.
One or more parameters are invalid. This Windows error indicates that a parameter passed into the function is invalid. This error also occurs with WSAWaitForMultipleEvents when the event count parameter is not valid.

An application used a WinSock function which directly maps to a Win32 function. The Win32 function is indicating a problem with one or more parameters.


258—WSA_WAIT_TIMEOUT
Operation timed out. This Windows error indicates that the overlapped operation did not complete in the specified time.


995—WSA_OPERATION_ABORTED
Overlapped operation aborted. This Windows error indicates that an overlapped I/O operation was canceled because of the closure of a socket. In addition, this error can occur when executing the SIO_FLUSH ioctl command.


996—WSA_IO_INCOMPLETE
(OS dependent) Overlapped I/O event object not in signaled state.
Overlapped I/O event object is not in a signaled state. This Windows error is also associated with overlapped I/O. It is seen when calling WSAGetOverlappedResults and indicates that the overlapped I/O operation has not yet completed.

The application has tried to determine the status of an overlapped operation which is not yet completed. Applications that use WSAGetOverlappedResult() (with the fWait flag set to false) in a polling mode to determine when an overlapped operation has completed will get this error code until the operation is complete.


997—WSA_IO_PENDING
(OS dependent) Overlapped operations will complete later.
Overlapped operations will complete later. When making an overlapped I/O call with a Winsock function, this Windows error is returned to indicate that the operation is pending and will complete later. See Chapter 5 for a discussion of overlapped I/O.

The application has initiated an overlapped operation which cannot be completed immediately. A completion indication will be given at a later time when the operation has been completed.


—WSAPROVIDERFAILEDINIT (OS dependent) Unable to initialize a service provider.
Either a service provider's DLL could not be loaded (LoadLibrary() failed) or the provider's WSPStartup/NSPStartup function failed.


—WSAINVALIDPROCTABLE (OS dependent) Invalid procedure table from service provider.
A service provider returned a bogus proc table to WS2_32.DLL. (Usually caused by one or more of the function pointers being NULL.)


—WSAINVALIDPROVIDER (OS dependent) Invalid service provider version number.
A service provider returned a version number other than 2.2.

(( 尚有遺漏...待補 ))