CrEvent.C

#include <windows.h>

#include "CrEvent.h"

HINSTANCE hInst; // current instance

LPCTSTR lpszAppName = "MyApp";

LPCTSTR lpszTitle = "My Application";

Int apientry WinMain( hinstance hInstance, hinstance hPrevInstance,

LPTSTR lpCmdLine, int nCmdShow)

{

MSG msg;

HWND hWnd;

WNDCLASSEX wc;

// Register the main application window class.

//............................................

wc.style = CS_HREDRAW | CS_VREDRAW;

wc.lpfnWndProc = (WNDPROC)WndProc;

wc.cbClsExtra = 0;

wc.cbWndExtra = 0;

wc.hInstance = hInstance;

wc.hIcon = LoadIcon( hInstance, lpszAppName );

wc.hCursor = LoadCursor(NULL, IDC_ARROW);

wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);

wc.lpszMenuName = lpszAppName;

wc.lpszClassName = lpszAppName;

wc.cbSize = sizeof(WNDCLASSEX);

wc.hIconSm = LoadImage( hInstance, lpszAppName,

IMAGE_ICON, 16, 16,

LR_DEFAULTCOLOR );

if ( !RegisterClassEx( &wc ) )

return( FALSE );

hInst = hInstance;

// Create the main application window.

//....................................

hWnd = CreateWindow( lpszAppName,

lpszTitle,

WS_OVERLAPPEDWINDOW,

CW_USEDEFAULT, 0,

CW_USEDEFAULT, 0,

NULL,

NULL,

hInstance,

NULL

);

if ( !hWnd )

return( FALSE );

ShowWindow( hWnd, nCmdShow );

UpdateWindow( hWnd );

while( GetMessage( &msg, NULL, 0, 0) )

{

TranslateMessage( &msg );

DispatchMessage( &msg );

}

return( msg.wParam );

}

#define SEMAPHORE_MAX_COUNT 10

LPCTSTR lpszReadSem = "Read Semaphore";

LPCTSTR lpszWriteEvent = "Write Event";

HANDLE hSemRead = NULL;

HANDLE hEventWrite = NULL;

LRESULT CALLBACK WndProc( HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam )

{

switch( uMsg )

{

case WM_CREATE:

// Make the two synchronization objects.

//......................................

hSemRead = CreateSemaphore( NULL, 10, 10, lpszReadSem );

hEventWrite = CreateEvent( NULL, TRUE, TRUE, lpszWriteEvent );

break;

case WM_COMMAND :

switch( LOWORD( wParam ) )

{

case IDM_READ:

{

HANDLE hTmpSemRead;

HANDLE hTmpEventWrite;

hTmpSemRead= OpenSemaphore( SEMAPHORE_ALL_ACCESS, FALSE, lpszReadSem );

hTmpEventWrite = OpenEvent( SYNCHRONIZE, FALSE, lpszWriteEvent );

SetWindowText( hWnd, "Waiting for all Writes to Finish" );

// Check that write manual reset event is signaled.

//.................................................

WaitForSingleObject( hEventWrite, INFINITE );

// Wait for semaphore.

//....................

WaitForSingleObject( hSemRead, INFINITE );

// Do the simulated read.

//.......................

SetWindowText( hWnd, "Reading" );

Sleep( 5000 );

// Release semaphore.

//...................

ReleaseSemaphore( hSemRead, 1, NULL );

SetWindowText( hWnd, "Done Reading" );

// Close the temporary handles.

//.............................

CloseHandle( hTmpSemRead );

CloseHandle( hTmpEventWrite );

}

break;

case IDM_WRITE:

{

DWORD dwSemaphoreCount = 0;

HANDLE hTmpSemRead;

HANDLE hTmpEventWrite;

hTmpSemRead = OpenSemaphore( SEMAPHORE_ALL_ACCESS, FALSE, lpszReadSem );

hTmpEventWrite = OpenEvent( SYNCHRONIZE, FALSE, lpszWriteEvent );

// Wait for manual-reset event: it becomes nonsignaled.

//.....................................................

SetWindowText( hWnd, "Waiting for Write Event" );

WaitForSingleObject( hEventWrite, INFINITE );

ResetEvent( hEventWrite );

SetWindowText( hWnd, "Waiting for All Reads to Finish" );

// Release semaphore until its count is the maximum allowed.

//..........................................................

while ( dwSemaphoreCount != SEMAPHORE_MAX_COUNT )

{

WaitForSingleObject( hSemRead, INFINITE );

ReleaseSemaphore( hSemRead, 1, &dwSemaphoreCount );

dwSemaphoreCount++;

}

SetWindowText( hWnd, "Writing" );

// Do the simulated write.

//........................

Sleep( 10000 );

SetWindowText( hWnd, "Done Writing" );

// SetEvent: event object becomes signaled.

//.........................................

SetEvent( hEventWrite );

// Close the handles.

//...................

CloseHandle( hTmpSemRead );

CloseHandle( hTmpEventWrite );

}

break;

case IDM_ABOUT :

DialogBox( hInst, "AboutBox", hWnd, (DLGPROC)About );

break;

case IDM_EXIT :

DestroyWindow( hWnd );

break;

}

break;

case WM_DESTROY :

if ( hSemRead )

CloseHandle( hSemRead );

if ( hEventWrite )

CloseHandle( hEventWrite );

PostQuitMessage(0);

break;

default :

return( DefWindowProc( hWnd, uMsg, wParam, lParam ) );

}

return( 0L );

}

LRESULT CALLBACK About( HWND hDlg,

UINT message,

WPARAM wParam,

LPARAM lParam)

{

switch (message)

{

case WM_INITDIALOG:

return (TRUE);

case WM_COMMAND:

if ( LOWORD(wParam) == IDOK

|| LOWORD(wParam) == IDCANCEL)

{

EndDialog(hDlg, TRUE);

return (TRUE);

}

break;

}

return (FALSE);

}

Определение структуры SECURITY_ATTRIBUTES

typedef struct _SECURITY_ATTRIBUTES {

DWORD nLength;

LPVOID lpSecurityDescriptor;

BOOL blnheritHandle; } SECURITY_ATTRIBUTES;

Члены

nLength DWORD: Размер структуры в байтах.

lpSecurityDescriptor LPVOID: Указатель на дескриптор защиты объекта, который управляет совместным использованием этого объекта. Если установлено значение NULL, для объекта можно назначить используемый по умолчанию деск­риптор защиты вызывающего процесса. В Windows 9.x этот член игнори­руется.

blnheritHandle BOOL: Если возвращаемый дескриптор наследуется новыми порожденны­ми процессами, устанавливается значение TRUE. В противном случае – значение FALSE.