6-3

it2022-05-09 25

/* * IoByAPC.c * * Sample code for Multithreading Applications in Win32 * This is from Chapter 6, Listing 6-3 * * Demonstrates how to use APC's (asynchronous * procedure calls) instead of signaled objects * to service multiple outstanding overlapped * operations on a file. */

#define WIN32_LEAN_AND_MEAN#include <stdio.h>#include <stdlib.h>#include <windows.h>#include "MtVerify.h"

//// Constants//#define MAX_REQUESTS 5#define READ_SIZE 512#define MAX_TRY_COUNT 5

//// Function prototypes//void CheckOsVersion();int QueueRequest(int nIndex, DWORD dwLocation, DWORD dwAmount);

//// Global variables//

// Need a single event object so we know when all I/O is finishedHANDLE ghEvent;// Keep track of each individual I/O operationOVERLAPPED gOverlapped[MAX_REQUESTS];// Handle to the file of interest.HANDLE ghFile;// Need a place to put all this datachar gBuffers[MAX_REQUESTS][READ_SIZE];int nCompletionCount;

/* * I/O Completion routine gets called * when app is alertable (in WaitForSingleObjectEx) * and an overlapped I/O operation has completed. */VOID WINAPI FileIOCompletionRoutine( DWORD dwErrorCode, // completion code DWORD dwNumberOfBytesTransfered, // number of bytes transferred LPOVERLAPPED lpOverlapped // pointer to structure with I/O information ){ // The event handle is really the user defined data int nIndex = (int)(lpOverlapped->hEvent); printf("Read #%d returned %d. %d bytes were read.\n", nIndex, dwErrorCode, dwNumberOfBytesTransfered);

if (++nCompletionCount == MAX_REQUESTS) SetEvent(ghEvent); // Cause the wait to terminate}

int main(){ int i; char szPath[MAX_PATH];

CheckOsVersion();

// Need to know when to stop MTVERIFY( ghEvent = CreateEvent( NULL, // No security TRUE, // Manual reset - extremely important! FALSE, // Initially set Event to non-signaled state NULL // No name ) );

GetWindowsDirectory(szPath, sizeof(szPath)); strcat(szPath, "http://www.cnblogs.com/nanshouyong326/admin/file://WINHLP32.EXE/"); // Open the file for overlapped reads ghFile = CreateFile( szPath, GENERIC_READ, FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL ); if (ghFile == INVALID_HANDLE_VALUE) { printf("Could not open %s\n", szPath); return -1; }

// Queue up a few requests for (i=0; i<MAX_REQUESTS; i++) { // Read some bytes every few K QueueRequest(i, i*16384, READ_SIZE); }

printf("QUEUED!!\n");

// Wait for all the operations to complete. for (;;) { DWORD rc; rc = WaitForSingleObjectEx(ghEvent, INFINITE, TRUE ); if (rc == WAIT_OBJECT_0) break; MTVERIFY(rc == WAIT_IO_COMPLETION); }

CloseHandle(ghFile);

return EXIT_SUCCESS;}

/* * Call ReadFileEx to start an overlapped request. * Make sure we handle errors that are recoverable. */int QueueRequest(int nIndex, DWORD dwLocation, DWORD dwAmount){ int i; BOOL rc; DWORD err;

gOverlapped[nIndex].hEvent = (HANDLE)nIndex; gOverlapped[nIndex].Offset = dwLocation;

for (i=0; i<MAX_TRY_COUNT; i++) { rc = ReadFileEx( ghFile, gBuffers[nIndex], dwAmount, &gOverlapped[nIndex], FileIOCompletionRoutine );

// Handle success if (rc) { // asynchronous i/o is still in progress printf("Read #%d queued for overlapped I/O.\n", nIndex); return TRUE; }

err = GetLastError();

// Handle recoverable error if ( err == ERROR_INVALID_USER_BUFFER || err == ERROR_NOT_ENOUGH_QUOTA || err == ERROR_NOT_ENOUGH_MEMORY ) { Sleep(50); // Wait around and try later continue; }

// Give up on fatal error. break; }

printf("ReadFileEx failed.\n"); return -1;}

//// Make sure we are running under an operating// system that supports overlapped I/O to files.//void CheckOsVersion(){ OSVERSIONINFO ver; BOOL bResult;

ver.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);

bResult = GetVersionEx((LPOSVERSIONINFO) &ver);

if ( (!bResult) || (ver.dwPlatformId != VER_PLATFORM_WIN32_NT) ) { fprintf(stderr, "IoByAPC must be run under Windows NT.\n"); exit(EXIT_FAILURE); }

}

routu

00401000 . 8B4424 08 mov eax, dword ptr [esp+8]00401004 . 8B5424 0C mov edx, dword ptr [esp+C]00401008 . 8B4C24 04 mov ecx, dword ptr [esp+4]0040100C . 50 push eax ; /<%d>0040100D . 8B42 10 mov eax, dword ptr [edx+10] ; |00401010 . 51 push ecx ; |<%d>00401011 . 50 push eax ; |<%d>00401012 . 68 10304000 push 00403010 ; |format = "Read #%d returned %d. %d bytes were read.",LF,""00401017 . FF15 3C204000 call dword ptr [<&MSVCRTD.printf>] ; \printf0040101D . A1 98314000 mov eax, dword ptr [403198]00401022 . 83C4 10 add esp, 1000401025 . 40 inc eax00401026 . 83F8 05 cmp eax, 500401029 . A3 98314000 mov dword ptr [403198], eax0040102E . 75 0D jnz short 0040103D00401030 . 8B0D 90314000 mov ecx, dword ptr [403190]00401036 . 51 push ecx ; /hEvent => NULL00401037 . FF15 00204000 call dword ptr [<&KERNEL32.SetEvent>] ; \SetEvent0040103D > C2 0C00 retn 0C

ida

转载于:https://www.cnblogs.com/nanshouyong326/archive/2010/07/09/1774396.html

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