內容。經過仔細咀嚼和推敲后，更能得到一些編寫優質程序的靈感。
    該程序在FTP公司的PCTCP支撐環境下調試通過，不過只要讀者擁有任何符
合Windows Sockets 1.1規范的實現，也能順利執行該程序。


3.4.1 源程序目錄
1. wshout.c wshout主程序
2. wshout.h wshout頭文件
3. wshout.rc wshout資源文件
4. ushout.c UDP客戶機程序
5. ulisten.c UDP服務器程序
6. tshout.c TCP客戶機程序
7. tlisten.c TCP服務器程序
8. errno.c 獲取WSAE*錯誤描述字符串程序
9. resolve.c 客戶機/服務器啟動程序
  
    在編譯本程序時，筆者用的是BC3.1，只需做一個PRJ工程文件，將上述.c文
件及winsock.lib包括進來就行了。請注意winsock.h應在include目錄或當前目錄中，
winsock.lib可利用winsock.dll通過implib工具來建立。如果讀者使用其他的編譯器，
可自行作相應的調整，在此不再贅述。

3.4.2 程序邏輯結構

 

3.4.3 源程序清單及注釋
3.4.3.1 wshout.c清單
/*
 * 文件名: WSHOUT.C
 */

/* MSC Include files: */
#include <stdio.h>
#include <io.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>

#include "wshout.h"

#define MAJOR_VERSION	1
#define MINOR_VERSION	2
#define WSA_MAKEWORD(x,y)	((y) * 256 + (x)) /* HI:Minor, LO:Major */

HANDLE	hInst;			/* 進程實例句柄 */
HWND	hOurWnd;		/* 主窗口句柄 */
HWND	hMainDlg;		/* 主對話框句柄 */

int ret;			/* 工作變量 */
char	prbuf[PRBUF_LEN];	/* 用于顯示文本的工作緩沖區 */

SOCKET sd;			/* 用于監聽連接的套接口描述字 */
long temporary_option   = 0L;	/* 缺省為阻塞模式 */
long blocking_option    = 0L;	/* 阻塞模式的全局標識 */
int run_cancelled	= 0;	/* 指示何時按下了取消按鈕 */
int len = 1024;			/* 一次寫的字節數 */
BOOL	running = FALSE;	/* 程序的運行狀態 */
const int iTCP = 1;		/* 指定為TCP Shout */
const int iUDP = 2;		/* 指定為UDP Shout */
int iProto	= 1;		/* 缺省為TCP Shout */
int iPortNo	= SOCK_SHOUT;	
int temporary_protocol  = 1;	/* 在Settings()中使用 */
int iShout  = 1;
int iListen = 2;
int iClientOrServer = 1;	/* 缺省為Shout（客戶機）	*/
int tClientOrServer = 1;	/* 在Settings()中使用 */
char HostModeBuf[20];/* 保存模式字符串 */
WORD VersionReqd;
LPWSADATA lpmyWSAData;

int PASCAL
WinMain (HANDLE hInstance,HANDLE hPrevInstance,LPSTR lpCmdLine,int 
nCmdShow)
{

    HWND hWnd;
    MSG msg;
    BOOL InitApp(HANDLE);

    if (!hPrevInstance)
    if (!InitApp(hInstance))
	    return (NULL);

    hInst = hInstance;

    hWnd = CreateWindow("MainMenu",
	"Windows Shout",
	WS_OVERLAPPEDWINDOW | WS_SYSMENU | WS_MINIMIZEBOX,
	CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        NULL,
        NULL,
        hInstance,
        NULL);

    if (!hWnd)
	return (NULL);

    hOurWnd = hWnd;
    
    while (GetMessage(&msg, NULL, NULL, NULL)) {
	TranslateMessage(&msg); /* 翻譯虛擬鍵碼 */
	DispatchMessage(&msg);
    }

    return (msg.wParam);
}

BOOL InitApp(HANDLE hInstance)
{
    HANDLE hMemory;
    PWNDCLASS pWndClass;
    BOOL bSuccess;

    hMemory = LocalAlloc(LPTR, sizeof(WNDCLASS));
    pWndClass = (PWNDCLASS) LocalLock(hMemory);
    pWndClass->hCursor = LoadCursor(NULL, IDC_ARROW);
    pWndClass->hIcon = LoadIcon(hInstance, (LPSTR) "SHOUT");
    pWndClass->lpszMenuName = (LPSTR) "MainMenu";
    pWndClass->lpszClassName = (LPSTR) "MainMenu";
    pWndClass->hbrBackground = GetStockObject(WHITE_BRUSH);
    pWndClass->hInstance = hInstance;
    pWndClass->style = NULL;
    pWndClass->lpfnWndProc = ShoutWndProc;

    bSuccess = RegisterClass(pWndClass);

    LocalUnlock(hMemory);
    LocalFree(hMemory);
    return (bSuccess);
}

long FAR PASCAL ShoutWndProc(HWND hWnd, WORD message,WORD wParam, 
LONG lParam)
{
    FARPROC lpDialogBoxProc;

    switch (message){
	case WM_CREATE:
	    
	    /* Put up the dialog box */
	    lpDialogBoxProc = MakeProcInstance(DialogProc, hInst);
	    DialogBox (hInst, (LPSTR) "MainDialog", hWnd, lpDialogBoxProc) ;
	    FreeProcInstance(lpDialogBoxProc);
	    PostMessage(hWnd, WM_DESTROY, 0, 0L);
	    break;
	    
	case WM_DESTROY:
	    PostQuitMessage(0);
	    break;
	
	default:
	    return(DefWindowProc(hWnd, message, wParam, lParam));
	}
    return NULL;

}


BOOL FAR PASCAL DialogProc(HWND hOurDlg, WORD message, WORD wParam, 
LONG lParam)
{
    FARPROC lpProcAbout;
    FARPROC lpProcSettings;
    long lret;
    WORD wMajorVersion, wMinorVersion;
    char hostnm[64];		/* 包含主機名的工作緩沖區 */
 
    switch (message) {
	case WM_INITDIALOG:
	    /* 選擇缺省主機 */
	    SetDlgItemText(hOurDlg, IDD_HNAME, "");
	    SendDlgItemMessage(hOurDlg,		/* 對話框句柄 */
		IDD_HNAME,			/* 向何處發送msg */
		EM_SETSEL,			/* 選擇字符 */
		NULL,				/* 附加信息 */
		MAKELONG(0, 0x7fff));		/* 全部內容 */
	    SetFocus(GetDlgItem(hOurDlg, IDD_HNAME));
	    
	    /* 初始化 */
	    hMainDlg = hOurDlg;  /* 保存自己的窗口句柄 */
	    SetDlgItemText(hOurDlg, IDD_COHOST,"Shout to:");
	    wMajorVersion = MAJOR_VERSION;
	    wMinorVersion = MINOR_VERSION;
	    VersionReqd=WSA_MAKEWORD(wMajorVersion, wMinorVersion);
  
	    lpmyWSAData = (LPWSADATA)_calloc(1, sizeof(WSADATA));
	    
	    ret = WSAStartup(VersionReqd, lpmyWSAData);
	    
	    if (ret != 0){
		wshout_err (hOurDlg, WSAGetLastError(), "WSAStartup()");
	    }
	    
	    return (TRUE); 

	case WM_CLOSE:
	    PostMessage(hOurDlg, WM_COMMAND, IDM_EXIT, 0L);
	    break;
	    
	case WM_SYSCOMMAND:
	    SendMessage(hOurWnd, message, wParam, lParam);
	    break;
	    
	case WM_COMMAND:
	    switch (wParam) {
	    case IDD_CONNECT:		/* 按下連接按鈕 */
	    case IDM_START:		/* 選擇了Start菜單項 */
		run_cancelled = FALSE;
		/* 不能重入 */
		if (running){
		    MessageBox(hOurWnd,"Shout is already running !",
			"Shout", MB_OK | MB_APPLMODAL | MB_ICONEXCLAMATION);
		    return FALSE;
		}
		ClearBoxes(hOurDlg);
		running = TRUE;

		if (iClientOrServer == iShout) {
		   /* 確保有主機名 */
		   if (GetDlgItemText (hOurDlg, IDD_HNAME, hostnm, 80) < 2) {
		       MessageBeep(0);
		       SetDlgItemText(hOurDlg, 
			              IDD_COMMENT,"No hostname specified");
		       running = FALSE;
		       break;
		   }
		   sd = ResolveAndConnectHost((char FAR *)hostnm,hOurDlg,iProto,
		                              iPortNo);
		   if (sd == SOCKET_ERROR) {/* 無法創建套接口 */
		       running = FALSE;
		       break;
		   }
	        }
		else {
		   sd = GetSocketAndBind(hOurDlg, iProto, iPortNo);
		   if (sd == SOCKET_ERROR) {
		    running = FALSE;
		    break;
		   }
	        }
		
		/* Set the I/O mode of the socket */
		if (blocking_option) {
		    lret = 1L;  /* 非阻塞模式 */
		    ioctlsocket(sd, FIONBIO, (u_long FAR *) &lret);
		}
		else {
		    lret = 0L; /* 阻塞模式 */
		    ioctlsocket(sd, FIONBIO, (u_long FAR *) &lret);
		}
		
		if (iClientOrServer == iShout) {  /* SHOUT */
		    /* 產生數據并寫入套接口 */
		    if (iProto == iTCP) 
			lret = TWriteData(sd, hOurDlg, len);
		    else /* UDP */
			lret = UWriteData(sd, hOurDlg, len);
		}
		else {	/* LISTEN */
		    if (iProto == iTCP)
			lret = TReadData(sd,hOurDlg, len);
		    else /* UDP */
			lret = UReadData(sd,hOurDlg, len);
		}
		
		closesocket(sd);
		running = FALSE;
		break;
		
	    case IDD_CANCEL:
		if (running) {
		    /* 停止 */
		    ret = WSACancelBlockingCall();
		    run_cancelled = TRUE;
		    if (ret == SOCKET_ERROR) {
			/* WSANOTINITIALISED or WSAENETDOWN or WSAEINVAL */
			if (h_errno == WSAENETDOWN) {
			    /* Watch out for hAcceptSock! */
			    /* close what is left of the connection */
			    closesocket(sd);
			}
		    }
		}
		break;
		
	    case IDM_EXIT:
		ret = WSACleanup();
		if (ret == SOCKET_ERROR && h_errno == WSAEINPROGRESS){
		    MessageBox(hOurWnd, 
			"Data transfer in progress.\nStop transfer first.",
			"WndProc()", MB_OK | MB_APPLMODAL|MB_ICONINFORMATION);
		    break; /* 一個套接口正處于阻塞狀態 */
		}
		
		_free((char NEAR *) lpmyWSAData);
		EndDialog(hOurDlg, TRUE) ; /* 退出 */
		break;
		
	    case IDM_ABOUT:
		lpProcAbout = MakeProcInstan