{"componentChunkName":"component---src-templates-post-template-js","path":"/windows-createfile-en","result":{"data":{"markdownRemark":{"id":"70a7bef7-aa3b-5e3c-8c3f-38032c5adbc1","html":"
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This page has been machine-translated from the original page.

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I wanted a tool that could obtain file handles with arbitrary settings for testing, so I created a simple one.

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Table of Contents

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Source Code

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#include <windows.h>\n#include <iostream>\n#include <string>\n\n# define FILE_SHARE_NONE 0x00000000\n\nint isEmpty(std::wstring text) {\n\n    if (text.empty()) {\n        std::wcerr << L"Input is empty. Using default path." << std::endl;\n        return 1;\n    }\n\n    return 0;\n}\n\nstd::wstring handleInput(std::wstring text) {\n    while (!text.empty() && (text.back() == L'\\n' || text.back() == L'\\r' || text.back() == L' '))\n        text.pop_back();\n\n    return text;\n}\n\nHANDLE createFileHandle(const std::wstring& path, std::wstring& desiredAccess, std::wstring& shareMode) {\n    \n    DWORD dwDesiredAccess = 0;\n    DWORD dwShareMode = 0;\n\n    if (desiredAccess == L"1") {\n        dwDesiredAccess = GENERIC_READ;\n    }\n    else if (desiredAccess == L"2") {\n        dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;\n    }\n    else {\n        std::wcerr << L"Invalid desired access input." << std::endl;\n        return NULL;\n}\n\n    if (shareMode == L"1") {\n        dwShareMode = FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE;\n    }\n    else if (shareMode == L"2") {\n        dwShareMode = FILE_SHARE_READ;\n    }\n    else if (shareMode == L"3") {\n        dwShareMode = FILE_SHARE_NONE;\n    }\n    else {\n        std::wcerr << L"Invalid share mode input." << std::endl;\n        return NULL;\n    }\n\n    HANDLE hFile = CreateFileW(\npath.c_str(), // lpFileName\ndwDesiredAccess, // dwDesiredAccess\ndwShareMode, // dwShareMode\nNULL, // lpSecurityAttributes\n        OPEN_ALWAYS, // dwCreationDisposition\nFILE_ATTRIBUTE_NORMAL, // dwFlagsAndAttributes\nNULL // hTemplateFile\n    );\n\n    if (hFile == INVALID_HANDLE_VALUE) {\n        std::wcerr << L"Failed to open file. Error: " << GetLastError() << std::endl;\n        return NULL;\n    }\n    std::wcout << L"File opened successfully." << std::endl;\n\n    return hFile;\n\n}\n\nint wmain()\n{\n// Input target file path\n    std::wcout << L"Input target file path(Default C:\\\\Windows\\\\Temp\\\\testfile.txt): ";\n    std::wstring path;\n    std::getline(std::wcin, path);\n\npath = handleInput(path);\n    if (isEmpty(path)) {\npath = L"C:\\\\Windows\\\\Temp\\\\testfile.txt";\n    }\n\n// Input desired access\n    std::wcout << L"\\nWhat is desired access?\\n1:\\"GENERIC_READ\\"\\n2:\\"GENERIC_READ | GENERIC_WRITE\\" : ";\n    std::wstring desiredAccess;\n    std::getline(std::wcin, desiredAccess);\n\ndesiredAccess = handleInput(desiredAccess);\n    if (isEmpty(desiredAccess))\nreturn 1;\n \n// Input share mode\n    std::wcout << L"\\nWhat is share mode?\\n1:\\"FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE\\"\\n2:\\"FILE_SHARE_READ\\"\\n3:\\"FILE_SHARE_NONE\\" : ";\n    std::wstring shareMode;\n    std::getline(std::wcin, shareMode);\n\nshareMode = handleInput(shareMode);\nif (isEmpty(shareMode))\nreturn 1;\n    \nHANDLE hFile = createFileHandle(path, desiredAccess, shareMode);\n\n    std::wcout << L"\\nPlease Enter key to close.";\n    std::wstring tmp;\n    std::getline(std::wcin, tmp);\n\n    CloseHandle(hFile);\n\n    return 0;\n}
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Operation Check

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When you run the tool built from the code above, you can execute CreateFileW by specifying the dwDesiredAccess and dwShareMode options as shown below.

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This makes it easy to verify behaviors such as CreateFile failing with SHARING VIOLATION when you execute CreateFile with FILE_SHARE_NONE against a file whose handle has already been obtained with FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE.

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Summary

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GitHub Copilot’s development assistance is so intelligent that writing code has become incredibly easy.

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I also wrote this article in 10 minutes.

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