1 / 11

Other Thread Synchronization Functions

Other Thread Synchronization Functions. 井民全製作. Introduction. Asynchronous I/O 架構. 主要的 thread 發出 I/O 的動作 繼續後面 的工作 當 I/O 完成時 , 自動呼叫 call back fuction. WriteFileEx. 處理 I/O. 1. I/O 完成 2. 主 thread 進入 Alerable 狀態. 繼續工作. Call back 處理函式. SleepEx(INFINITE,TRUE).

jase
Télécharger la présentation

Other Thread Synchronization Functions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Other Thread Synchronization Functions 井民全製作

  2. Introduction

  3. Asynchronous I/O 架構 • 主要的 thread 發出 I/O 的動作 • 繼續後面的工作 • 當 I/O 完成時, 自動呼叫 call back fuction WriteFileEx 處理I/O 1. I/O完成 2. 主 thread 進入Alerable 狀態 繼續工作 Call back 處理函式 SleepEx(INFINITE,TRUE)

  4. Asynchronous Write void ShowError(); VOID CALLBACK IoCompletionRoutine(DWORD dwErrorCode,DWORD dwNumberOfBytesTransfered, LPOVERLAPPED lpOverlapped); #include <iostream> using namespace std; int main(int argc, TCHAR* argv[], TCHAR* envp[]){ HANDLE hFile = CreateFile(_T("c:\\myfile.txt"), // file to create GENERIC_WRITE, // open for writing 0, // do not share NULL, // default security CREATE_ALWAYS, // overwrite existing FILE_ATTRIBUTE_NORMAL | // normal file FILE_FLAG_OVERLAPPED, // asynchronous I/O NULL); // no attr. template if (hFile == INVALID_HANDLE_VALUE) { ShowError(); return -1; } 完整範例: AsynchronousWriteDemo

  5. // Step 1: 配置 Overlapped 結構 空間 LPOVERLAPPED Overlapped; Overlapped =(LPOVERLAPPED) LocalAlloc(LMEM_ZEROINIT, sizeof(OVERLAPPED)); if(!Overlapped){ ShowError(); return -1; } // Step 2: 定義要寫入的資料 Overlapped->Offset = 0; // 設定起始寫入指標(low word) Overlapped->OffsetHigh = 0; // 起始寫入指標(high word) LPTSTR lpBuffer=_T("jING_TEST"); // 指定要寫入的資料 DWORD dwTransferCount=lstrlen(lpBuffer)*sizeof(TCHAR); // 計算寫入資料的長度 (byte) // Step 3: 非同步寫入 BOOL bSucc=WriteFileEx(hFile,lpBuffer, dwTransferCount, Overlapped ,IoCompletionRoutine); if(!bSucc){ ShowError(); } // Step 4: 作其他事情 for(int i=0;i<10;i++){ cout << i <<"秒"<< endl; Sleep(1000); } 初始=0 Call back function 要寫入的資料 Overlapped 結構

  6. // Step 5: 等待 I/O 完成 (你必須使用 WaitForSingleObjectEx 等待, CallBack function 才會被呼叫) /* HANDLE hEvent=CreateEvent( NULL, // no security attributes FALSE, // auto-reset event object FALSE, // initial state is nonsignaled NULL); // unnamed object WaitForSingleObjectEx(hEvent,INFINITE,TRUE); */ // 當 CallBack function 完成時, 會自動 return SleepEx(INFINITE,TRUE); CloseHandle(hFile); cout << "主程式離開" << endl; getchar(); return 0; }

  7. Call Back Function // 當非同步寫入完成時且主程式進入 alerable 狀態, 會呼叫 call back fucntion VOID CALLBACK IoCompletionRoutine(DWORD dwErrorCode, DWORD dwNumberOfBytesTransfered, LPOVERLAPPED lpOverlapped) { // If an I/O error occurs, display the error and exit. if (dwErrorCode) { printf("FATAL I/O Error %ld I/O Context %lx.%lx\n", dwErrorCode, lpOverlapped, lpOverlapped->hEvent); ShowError(); ExitProcess(dwErrorCode); } MessageBox(NULL,_T("寫入完成"),_T("Message"),MB_OK); for(int i=0;i<10;i++) Sleep(1000); LocalFree(lpOverlapped); }

  8. Asynchronous Read • 使用 ReadFileEx • 檔案存取必須是 sector size的整數倍 • 讀寫動作的記憶體位址必須為 sector size 的整數倍 得到磁碟的 sector size DWORD SectorsPerCluster,BytesPerSector,NumberOfFreeClusters,TotalNumberOfClusters; GetDiskFreeSpace(NULL, &SectorsPerCluster, &BytesPerSector, &NumberOfFreeClusters,&TotalNumberOfClusters); Sector size char *buffer=(char*) VirtualAlloc(NULL,BytesPerSector, MEM_COMMIT,PAGE_READWRITE); 會幫我們自動作 aligned

  9. 程式的流程 Step 1: CreateFile Step 2: 配置 Overlapped 結構空間 Step 3: 設定要讀取資料位置 1. 讀取 sector size 2. 配置 buffer 存放記憶體 3. 執行讀取資料的動作

  10. int main(int argc, _TCHAR* argv[]){ HANDLE hFile; hFile = CreateFile("c:\\myfile.txt", // open myfile.txt GENERIC_READ, // open for reading 0, // do not share NULL, // no security OPEN_EXISTING, // existing file only FILE_FLAG_OVERLAPPED, NULL); // no attr. template if(hFile== INVALID_HANDLE_VALUE) ShowError(); // Step 1: 配置 Overlapped 結構 空間 LPOVERLAPPED Overlapped; Overlapped =(LPOVERLAPPED) LocalAlloc(LMEM_ZEROINIT, sizeof(OVERLAPPED)); if(!Overlapped){ ShowError(); return -1; } // Step 2: 設定要讀取資料位置 Overlapped->Offset = 0; // 設定起始讀取指標(low word) Overlapped->OffsetHigh = 0; // 起始讀取指標(high word)

  11. // 1. 存取檔案的大小是 sector size 的整數倍 (使用 GetDiskFreeSpace) DWORD SectorsPerCluster,BytesPerSector,NumberOfFreeClusters,TotalNumberOfClusters; GetDiskFreeSpace(NULL,&SectorsPerCluster,&BytesPerSector, &NumberOfFreeClusters,&TotalNumberOfClusters); // 2. 讀寫動作的記憶體位址必須為 sector size 的整數倍 (使用 VirtualAlloc) char *buffer=(char*) VirtualAlloc(NULL,BytesPerSector,MEM_COMMIT,PAGE_READWRITE); // 3. 執行讀取資料的動作 while(ReadFileEx(hFile,buffer,BytesPerSector,Overlapped,IoCompletionRoutine)!=0){ if(GetLastError() != ERROR_SUCCESS){ ShowError(); return -1; } SleepEx(INFINITE,TRUE); } // 4. 釋放記憶體 VirtualFree(buffer,0,MEM_RELEASE); 完整範例: AsynchronousReadDemo

More Related