{"id":10508,"date":"2024-03-14T12:14:31","date_gmt":"2024-03-14T12:14:31","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-use-the-c-file-functions-createfile-readfile-and-writefile\/"},"modified":"2025-08-04T00:29:50","modified_gmt":"2025-08-04T00:29:50","slug":"how-to-use-the-c-file-functions-createfile-readfile-and-writefile","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-use-the-c-file-functions-createfile-readfile-and-writefile\/","title":{"rendered":"C++ File I\/O: CreateFile, ReadFile &#038; WriteFile"},"content":{"rendered":"<p>In C++, you can use the functions CreateFile, ReadFile, and WriteFile to create, read, and write files.<\/p>\n<ol>\n<li>Create a file:<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code>HANDLE hFile = <span class=\"hljs-built_in\">CreateFile<\/span>(<span class=\"hljs-built_in\">TEXT<\/span>(<span class=\"hljs-string\">\"example.txt\"<\/span>), GENERIC_WRITE, <span class=\"hljs-number\">0<\/span>, <span class=\"hljs-literal\">NULL<\/span>, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, <span class=\"hljs-literal\">NULL<\/span>);\r\n<span class=\"hljs-keyword\">if<\/span> (hFile == INVALID_HANDLE_VALUE) {\r\n    <span class=\"hljs-comment\">\/\/ \u6587\u4ef6\u521b\u5efa\u5931\u8d25<\/span>\r\n    <span class=\"hljs-comment\">\/\/ \u5904\u7406\u9519\u8bef<\/span>\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>Write to file.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code>DWORD dwBytesWritten;\r\n<span class=\"hljs-type\">char<\/span> data[] = <span class=\"hljs-string\">\"Hello, World!\"<\/span>;\r\n<span class=\"hljs-keyword\">if<\/span> (!<span class=\"hljs-built_in\">WriteFile<\/span>(hFile, data, <span class=\"hljs-built_in\">sizeof<\/span>(data), &amp;dwBytesWritten, <span class=\"hljs-literal\">NULL<\/span>)) {\r\n    <span class=\"hljs-comment\">\/\/ \u5199\u5165\u6587\u4ef6\u5931\u8d25<\/span>\r\n    <span class=\"hljs-comment\">\/\/ \u5904\u7406\u9519\u8bef<\/span>\r\n}\r\n<\/code><\/pre>\n<ol>\n<li>Read the file.<\/li>\n<\/ol>\n<pre class=\"post-pre\"><code>DWORD dwBytesRead;\r\n<span class=\"hljs-type\">char<\/span> buffer[<span class=\"hljs-number\">100<\/span>];\r\n<span class=\"hljs-keyword\">if<\/span> (!<span class=\"hljs-built_in\">ReadFile<\/span>(hFile, buffer, <span class=\"hljs-built_in\">sizeof<\/span>(buffer), &amp;dwBytesRead, <span class=\"hljs-literal\">NULL<\/span>)) {\r\n    <span class=\"hljs-comment\">\/\/ \u8bfb\u53d6\u6587\u4ef6\u5931\u8d25<\/span>\r\n    <span class=\"hljs-comment\">\/\/ \u5904\u7406\u9519\u8bef<\/span>\r\n} <span class=\"hljs-keyword\">else<\/span> {\r\n    <span class=\"hljs-comment\">\/\/ \u8f93\u51fa\u8bfb\u53d6\u7684\u5185\u5bb9<\/span>\r\n    cout &lt;&lt; buffer &lt;&lt; endl;\r\n}\r\n<\/code><\/pre>\n<p>You need to include the Windows.h header file to use these functions. Also, remember to close the file handle after using the file.<\/p>\n<pre class=\"post-pre\"><code><span class=\"hljs-built_in\">CloseHandle<\/span>(hFile);\r\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>In C++, you can use the functions CreateFile, ReadFile, and WriteFile to create, read, and write files. Create a file: HANDLE hFile = CreateFile(TEXT(&#8220;example.txt&#8221;), GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); if (hFile == INVALID_HANDLE_VALUE) { \/\/ \u6587\u4ef6\u521b\u5efa\u5931\u8d25 \/\/ \u5904\u7406\u9519\u8bef } Write to file. DWORD dwBytesWritten; char data[] = &#8220;Hello, World!&#8221;; if (!WriteFile(hFile, data, sizeof(data), &amp;dwBytesWritten, [&hellip;]<\/p>\n","protected":false},"author":13,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[274,13151,890,3210,7040],"class_list":["post-10508","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-c","tag-createfile","tag-file-handling","tag-readfile","tag-windows-api"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v21.5 (Yoast SEO v21.5) - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>C++ File I\/O: CreateFile, ReadFile &amp; WriteFile - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Master C++ file operations with CreateFile, ReadFile &amp; WriteFile. 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