{"id":30640,"date":"2022-11-20T03:50:08","date_gmt":"2024-01-21T19:28:03","guid":{"rendered":"https:\/\/www.silicloud.com\/zh\/blog\/%e5%9c%a8php%e4%b8%ad%ef%bc%8cvoid%e6%98%af%e4%bb%80%e4%b9%88%e6%84%8f%e6%80%9d%ef%bc%9f\/"},"modified":"2025-08-12T20:08:38","modified_gmt":"2025-08-12T12:08:38","slug":"%e5%9c%a8php%e4%b8%ad%ef%bc%8cvoid%e6%98%af%e4%bb%80%e4%b9%88%e6%84%8f%e6%80%9d%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/zh\/blog\/%e5%9c%a8php%e4%b8%ad%ef%bc%8cvoid%e6%98%af%e4%bb%80%e4%b9%88%e6%84%8f%e6%80%9d%ef%bc%9f\/","title":{"rendered":"\u5728PHP\u4e2d\uff0cvoid\u662f\u4ec0\u4e48\u610f\u601d\uff1f"},"content":{"rendered":"<p>\u5728PHP\u7684\u4e0a\u4e0b\u6587\u4e2d\uff0c&#8221;void&#8221;\u4e00\u8bcd\u4ee5\u51e0\u79cd\u4e0d\u540c\u7684\u610f\u4e49\u88ab\u4f7f\u7528\u3002<\/p>\n<h2>\u7b80\u76f4void\u662f\u4ec0\u4e48\u610f\u601d<\/p>\n<blockquote><p>void\uff08\u30dc\u30a4\u30c9\uff09\u662f\u5728\u7f16\u7a0b\u8bed\u8a00\u4e2d\u7528\u4e8e\u8868\u793a&#8221;\u4ec0\u4e48\u4e5f\u6ca1\u6709&#8221;\u8fd9\u79cd\u610f\u4e49\u7684\u7c7b\u578b\u7684\u540d\u79f0\u3002\u5b83\u901a\u5e38\u4f5c\u4e3a\u539f\u59cb\u7c7b\u578b\u7684\u5173\u952e\u5b57\u6216\u4fdd\u7559\u5b57\u4f7f\u7528\u3002<\/p><\/blockquote>\n<p>\uff08\u4ece\u7ef4\u57fa\u767e\u79d11\u4e2d\u5f15\u7528\u7684\u65e0\u6548\uff08\u8ba1\u7b97\u673a\uff09\uff09<\/p>\n<p>\u5728C\u8bed\u8a00\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528void f(void)\u8fd9\u6837\u7684\u8bed\u6cd5\u6765\u63cf\u8ff0\u4e00\u4e2a\u201c\u4e0d\u63a5\u6536\u53c2\u6570\u5e76\u4e14\u4e0d\u8fd4\u56de\u53c2\u6570\u201d\u7684\u51fd\u6570\u7684\u539f\u578b\u3002<\/p>\n<h2>PHP\u624b\u518c\u4e2d\u7684voidPHP\uff1a\u5728\u672c\u6587\u6863\u4e2d\uff0c\u5173\u4e8e\u4f2a\u7c7b\u578b\u548c\u53d8\u91cf\u7684\u8bf4\u660e\u53ef\u4ee5\u5728\u624b\u518c\u4e2d\u627e\u5230\u3002<\/p>\n<blockquote><p>\u5f53\u8fd4\u56de\u503c\u7684\u7c7b\u578b\u4e3avoid\u65f6\uff0c\u8868\u793a\u8fd4\u56de\u503c\u6ca1\u6709\u610f\u4e49\u3002\u5982\u679c\u5728\u53c2\u6570\u5217\u8868\u4e2d\u4f7f\u7528void\uff0c\u5219\u8868\u793a\u8be5\u51fd\u6570\u4e0d\u63a5\u53d7\u53c2\u6570\u3002<\/p><\/blockquote>\n<p>\u5177\u4f53\u6765\u8bf4\uff0c\u5982\u4e0b\u6240\u793a\u3002<\/p>\n<blockquote><p>\u6807\u9898<\/p>\n<p>(PHP 4\uff0cPHP 5\uff0cPHP 7)<\/p>\n<p>header &#8211; \u53d1\u9001\u539f\u59cb\u7684HTTP\u5934\u4fe1\u606f<\/p>\n<p>\u8bf4\u660e<\/p>\n<p>void header ( string $string [, bool $replace = true [, int $http_response_code ]] )<\/p><\/blockquote>\n<p>\uff08PHP\uff1a\u5f15\u7528\u81ea\u624b\u518c\u7684\u6807\u5934\uff09<\/p>\n<p>\u8fd9\u610f\u5473\u7740header()\u51fd\u6570\u7684\u6267\u884c\u7ed3\u679c\u4e0d\u8fd4\u56de\u4efb\u4f55\u503c\u3002<\/p>\n<p>\u6362\u53e5\u8bdd\u8bf4\uff0c\u6267\u884c\u8bf8\u5982 $result = header($str); \u6216 var_dump(header($str)); \u8fd9\u6837\u7684\u64cd\u4f5c\u662f\u6beb\u65e0\u610f\u4e49\u7684\u3002\u867d\u7136\u6beb\u65e0\u610f\u4e49\uff0c\u4f46\u8fd9\u4e9b\u8fd4\u56de\u503c\u5b9e\u9645\u4e0a\u662fNULL\u3002<\/p>\n<blockquote><p>get_defined_vars \u51fd\u6570\u80fd\u591f\u4ee5\u6570\u7ec4\u7684\u5f62\u5f0f\u8fd4\u56de\u6240\u6709\u5df2\u7ecf\u5b9a\u4e49\u8fc7\u7684\u53d8\u91cf\u3002<\/p>\n<p>\u8bf4\u660e<\/p>\n<p>array get_defined_vars ( void )<\/p><\/blockquote>\n<p>\uff08PHP\uff1aget_defined_vars &#8211; \u624b\u518c\u5f15\u7528\uff09<\/p>\n<p>\u8fd9\u6b21\u7684\u53c2\u6570\u662f (void)\u3002\u8fd9\u4e0d\u8868\u793a\u671f\u671b\u7279\u6b8a\u53c2\u6570\uff0c\u800c\u8868\u793a\u5217\u8868\u7684\u5185\u5bb9\u4e3a\u7a7a\uff0c\u4e5f\u5c31\u662f\u8bf4\u53c2\u6570\u4e0d\u63a5\u6536\u4efb\u4f55\u5185\u5bb9\u3002\u5bf9\u4e8e\u8fd9\u6837\u7684\u51fd\u6570\uff0c\u867d\u7136\u4f20\u5165\u53c2\u6570\u901a\u5e38\u4e0d\u4f1a\u5f15\u53d1\u9519\u8bef\uff0c\u4f46\u5374\u662f\u6beb\u65e0\u610f\u4e49\u7684\u3002<\/p>\n<h2>\u5728PHPDoc\u4e2d\u7684void\u8fd9\u662f\u4e00\u79cd\u7c7b\u4f3c\u4e8ePHP\u624b\u518c\u4e2d\u7684@return\u6807\u7b7e\u7684\u4f2a\u7c7b\u578b\u3002<\/p>\n<p>\u6ca1\u6709\u8fd4\u56de\u503c\u7684\u51fd\u6570\uff0c\u5728PHPDoc\u7c7b\u578b\u6ce8\u91ca\u4e2d\uff0c\u53ef\u4ee5\u6309\u4ee5\u4e0b\u65b9\u5f0f\u4e66\u5199\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"cd\">\/**\r\n * @return void\r\n *\/<\/span>\r\n<span class=\"k\">function<\/span> <span class=\"n\">hoge<\/span><span class=\"p\">()<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"k\">echo<\/span> <span class=\"s2\">\"hoge\"<\/span><span class=\"p\">;<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>\u4e0e\u5176\u8bf4\u662f\u540e\u7eed\u7684\u7c7b\u578b\u58f0\u660e\uff0cPHPDoc\u5728\u8fd0\u884c\u65f6\u6ca1\u6709\u4efb\u4f55\u5f71\u54cd\u3002\u5b9e\u9645\u4e0a\uff0c\u5b83\u53ea\u662f\u666e\u901a\u7684\u6ce8\u91ca\u884c\uff0c\u6240\u4ee5\u5728PHP 7.1\u4ee5\u4e0b\u7248\u672c\u4e5f\u53ef\u4ee5\u81ea\u7136\u5730\u4f7f\u7528\u3002<\/p>\n<h2>PHP7.1\u7248\u672c\u4e2d\u7684`void`\u7c7b\u578b\u58f0\u660e\u5728PHP7\u4e2d\uff0c\u53ef\u4ee5\u5728\u8fd4\u56de\u503c\u4e2d\u8fdb\u884c\u7c7b\u578b\u58f0\u660e\uff1b\u7136\u800c\uff0c\u5728PHP7.1\u4e2d\uff0c\u8fd9\u4e00\u529f\u80fd\u5f97\u5230\u4e86\u8fdb\u4e00\u6b65\u589e\u5f3a\uff0c\u73b0\u5728\u8fd8\u53ef\u4ee5\u4f7f\u7528void\u5173\u952e\u5b57\u8fdb\u884c\u58f0\u660e\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">function<\/span> <span class=\"n\">hoge<\/span><span class=\"p\">():<\/span> <span class=\"kt\">void<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"k\">echo<\/span> <span class=\"s2\">\"hoge\"<\/span><span class=\"p\">;<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>\u8fd9\u4e2a\u7c7b\u578b\u58f0\u660e\u7684\u7279\u70b9\u662f\u8fd4\u56de\u503c\u4f1a\u5bfc\u81f4\u9519\u8bef\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"cp\">&lt;?php<\/span>\r\n\r\n<span class=\"k\">function<\/span> <span class=\"n\">a<\/span><span class=\"p\">():<\/span> <span class=\"kt\">void<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"k\">echo<\/span> <span class=\"s2\">\"a\"<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"kc\">false<\/span><span class=\"p\">)<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"k\">return<\/span> <span class=\"kc\">true<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"nf\">a<\/span><span class=\"p\">();<\/span>\r\n<span class=\"c1\">\/\/ Fatal error: A void function must not return a value in \/in\/ZidNI on line 7<\/span>\r\n<\/code><\/pre>\n<p>\u8fd9\u4e2a\u7279\u70b9\u8ba9\u4eba\u611f\u5230\u5b89\u5fc3\uff0c\u5373\u4f7f\u662f\u5728\u4e0d\u5b9e\u9645\u6267\u884c\u7684\u5904\u7406\u4e2d\uff0c\u53ea\u9700\u5728return\u8bed\u53e5\u4e2d\u5199\u5165\u8fd4\u56de\u503c\uff0c\u5c31\u80fd\u6355\u6349\u5230\u9519\u8bef\u3002<\/p>\n<p>\u6ca1\u6709\u53c2\u6570\u7684\u8fd4\u56de\u4e0d\u4f1a\u6709\u95ee\u9898\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"k\">function<\/span> <span class=\"n\">b<\/span><span class=\"p\">():<\/span> <span class=\"kt\">void<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"k\">if<\/span> <span class=\"p\">(<\/span><span class=\"nf\">foo<\/span><span class=\"p\">())<\/span> <span class=\"p\">{<\/span>\r\n        <span class=\"k\">return<\/span><span class=\"p\">;<\/span>\r\n    <span class=\"p\">}<\/span>\r\n\r\n    <span class=\"nf\">bar<\/span><span class=\"p\">();<\/span>\r\n    <span class=\"nf\">buz<\/span><span class=\"p\">();<\/span>\r\n\r\n    <span class=\"k\">return<\/span><span class=\"p\">;<\/span> <span class=\"c1\">\/\/ \u7701\u7565\u53ef\u80fd<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<h2>\u5de5\u5177\u652f\u63f4\u5f53\u4f60\u8bd5\u56fe\u4f7f\u7528\u8fd4\u56de\u503c\u4e3a\u7a7a\u7684\u51fd\u6570\u7684\u8fd4\u56de\u503c\u65f6\uff0cPhpStorm\u4f1a\u5c06\u5176\u7a81\u51fa\u663e\u793a\uff0c\u4ee5\u4fbf\u66f4\u5bb9\u6613\u7406\u89e3\u3002<\/p>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/657d086237434c4406be035f\/31-0.png\" alt=\"PhpStorm: 'void' function 'a' result used\" \/>\u6b64\u5916\uff0c\u7c7b\u4f3c\u4e8ePhan\u7684\u72ec\u7acb\u9759\u6001\u5206\u6790\u5de5\u5177\u4e5f\u80fd\u591f\u68c0\u6d4b\u5230\u8fd9\u4e2a\u95ee\u9898\u3002<\/p>\n<pre class=\"post-pre\"><code>funcs.php:8 PhanTypeVoidAssignment Cannot assign void return value\r\n<\/code><\/pre>\n<h2>\u5728PHP\u4e2d\uff0c\u662f\u4f7f\u7528PHPDoc\u8fd8\u662f\u7c7b\u578b\u58f0\u660e\u6765\u5199\u4ee3\u7801\uff1f\u53ea\u9700\u8981\u4e00\u4e2a\u9009\u9879\uff0c\u7528\u4e2d\u56fd\u4eba\u7684\u65b9\u5f0f\u6539\u5199\uff1a\u5173\u4e8ePHPDoc\u5f62\u5f0f\u7684\u7c7b\u578b\u6ce8\u91ca`@return void`\u4ee5\u53caPHP 7.1\u5f62\u5f0f\u7684\u7c7b\u578b\u58f0\u660e`void`\u7684\u9009\u62e9\uff0c\u53ea\u9700\u8981\u6839\u636e&#8221;\u4ee3\u7801\u662f\u5426\u53ea\u7528\u4e8ePHP 7.1\u53ca\u4ee5\u4e0a\u7248\u672c&#8221;\u6765\u51b3\u5b9a\uff0c\u4e0d\u4f1a\u6709\u4efb\u4f55\u95ee\u9898\u3002<\/p>\n<p>\u521a\u624d\u4ecb\u7ecd\u7684\u4e24\u4e2a\u5de5\u5177\uff0cPhpStorm\u548cPhan\uff0c\u5bf9\u4e8e\u8fd9\u4e24\u79cd\u5199\u6cd5\u90fd\u8ba4\u4e3a\u662f\u4e00\u6837\u7684\uff0c\u6240\u4ee5\u65e0\u8bba\u7528\u54ea\u4e2a\u5199\u90fd\u662f\u4e00\u6837\u7684\u3002\u5bf9\u4e8evoid\u7c7b\u578b\u58f0\u660e\uff0c\u63a8\u8350\u4f7f\u7528PHP 7.1\uff0c\u56e0\u4e3a\u5b83\u53ef\u4ee5\u5728\u5b9a\u4e49\u65f6\u8f7b\u677e\u68c0\u6d4b\u5230\u8fd4\u56de\u503c\u9519\u8bef\uff0c\u800c\u65e0\u9700\u989d\u5916\u5b89\u88c5\u7279\u6b8a\u5de5\u5177\u3002<\/p>\n<p>\u53ef\u4ee5\u5199\u4e24\u79cd\u5f62\u5f0f\uff0c\u4f46\u53ea\u662f\u5197\u957f\u800c\u5df2\uff0c\u6240\u4ee5\u6ca1\u6709\u5199\u4e24\u79cd\u7684\u597d\u5904\u3002\u53ea\u9700\u8981\u5199\u5176\u4e2d\u4e00\u79cd\u5c31\u53ef\u4ee5\u4e86\u3002\u5982\u679c\u660e\u786e\u4e0d\u4f1a\u5728PHP 7.1\u4ee5\u4e0b\u7248\u672c\u4e2d\u8fd0\u884c\u4ee3\u7801\uff0c\u90a3\u4e48\u7edf\u4e00\u4f7f\u7528void\u7c7b\u578b\u58f0\u660e\u4f1a\u66f4\u7b80\u6d01\u3002<\/p>\n<p>\u5982\u679c\u4f60\u60f3\u8981\u5728\u5e7f\u6cdb\u5e94\u7528\u7684\u5e93\u4e2d\u652f\u6301PHP7.1\u4ee5\u4e0b\u7684\u7248\u672c\uff0c\u5efa\u8bae\u4f7f\u7528PHPDoc\u683c\u5f0f\u7684@return void\u8fdb\u884c\u7f16\u5199\u3002<\/p>\n<h2>\u65e0\u8bba\u5982\u4f55\u90fd\u6ca1\u5173\u7cfb<\/p>\n<blockquote><p>PHP\u6d4b\u9a8c\uff1a\u5728\u4ee5\u4e0b\u5185\u5bb9\u4e2d\uff0c\u54ea\u4e00\u884c\u662f\u68c0\u6d4b\u5230\u8bed\u6cd5\u9519\u8bef\u7684\u6700\u9876\u90e8\u884c\uff1f\uff1f pic.twitter.com\/zwHXYaYuti\u2014 nya-n (@tadsan) February 15, 2018<\/p><\/blockquote>\n<pre class=\"post-pre\"><code><span class=\"cp\">&lt;?php<\/span>\r\n\r\n<span class=\"n\">namespace<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"k\">const<\/span> <span class=\"no\">void<\/span> <span class=\"o\">=<\/span> <span class=\"kc\">null<\/span><span class=\"p\">;<\/span> <span class=\"c1\">\/\/ 1<\/span>\r\n\r\n    <span class=\"k\">goto<\/span> <span class=\"n\">void<\/span><span class=\"p\">;<\/span>\r\n\r\n    <span class=\"k\">function<\/span> <span class=\"n\">void<\/span><span class=\"p\">(<\/span>     <span class=\"c1\">\/\/ 2<\/span>\r\n        <span class=\"nv\">$void<\/span> <span class=\"o\">=<\/span> <span class=\"n\">void<\/span>   <span class=\"c1\">\/\/ 3<\/span>\r\n    <span class=\"p\">):<\/span> <span class=\"kt\">void<\/span>            <span class=\"c1\">\/\/ 4<\/span>\r\n    <span class=\"p\">{<\/span>\r\n        <span class=\"nb\">var_dump<\/span><span class=\"p\">(<\/span><span class=\"n\">void<\/span><span class=\"p\">);<\/span>\r\n        <span class=\"k\">return<\/span> <span class=\"n\">void<\/span><span class=\"p\">;<\/span>   <span class=\"c1\">\/\/ 5<\/span>\r\n    <span class=\"p\">}<\/span>\r\n<span class=\"p\">}<\/span>\r\n\r\n<span class=\"kn\">namespace<\/span> <span class=\"nn\">void<\/span>\r\n<span class=\"p\">{<\/span>\r\n    <span class=\"n\">void<\/span><span class=\"o\">:<\/span>\r\n        <span class=\"nf\">void<\/span><span class=\"p\">(<\/span><span class=\"n\">void<\/span><span class=\"p\">);<\/span>\r\n<span class=\"p\">}<\/span>\r\n<\/code><\/pre>\n<p>void\u88ab\u6dfb\u52a0\u5230PHP7.1\u4e2d\u4f5c\u4e3a\u4f2a\u7c7b\u578b\u540d\uff0c\u5e76\u7528\u4e8e\u5176\u4ed6\u4fdd\u7559\u5b57\u3002<\/p>\n<blockquote><p>PHP 7.0.0 \u53ca\u4ee5\u540e\u7248\u672c\uff0c\u8fd9\u4e9b\u5173\u952e\u5b57\u53ef\u4ee5\u4f5c\u4e3a\u5c5e\u6027\u548c\u5e38\u91cf\u7684\u540d\u79f0\u4f7f\u7528\u3002\u540c\u65f6\uff0c\u5b83\u4eec\u8fd8\u53ef\u4ee5\u4f5c\u4e3a\u7c7b\u3001\u63a5\u53e3\u548c\u7279\u6027\u7684\u65b9\u6cd5\u540d\u79f0\u4f7f\u7528\u3002<\/p><\/blockquote>\n<p>\u4e0e PHP 7.0 \u4e2d\u4f5c\u4e3a\u65b9\u6cd5\u5141\u8bb8\u4f7f\u7528\u7684\u5173\u952e\u5b57\u5217\u8868\u4e0d\u540c\uff0c\u201c\u5176\u4ed6\u4fdd\u7559\u5b57\u201d \u53ea\u662f\u65e0\u6cd5\u4f5c\u4e3a\u7c7b\u540d\uff08\u5305\u62ec\u7279\u5f81\u548c\u63a5\u53e3\uff09\uff0c\u4f46\u53ef\u4ee5\u6b63\u5e38\u5b9a\u4e49\u4e3a\u51fd\u6570\u540d\u3001\u65b9\u6cd5\u540d\u3001\u547d\u540d\u7a7a\u95f4\u3001\u5e38\u91cf\u540d\u548c goto \u6807\u7b7e\u7b49\u7b26\u53f7\u3002<\/p>\n<p>\u8fd9\u6837\u505a\u5e76\u6ca1\u6709\u7279\u522b\u7684\u597d\u5904\uff0c\u6240\u4ee5\u8bf7\u5c06PHP\u6709\u8da3\u7684\u77e5\u8bc6\u7559\u5728\u90a3\u5c31\u597d\u4e86\u2026\u2026\u5fd8\u8bb0\u4e86\u4e5f\u6ca1\u5173\u7cfb\u3002<\/p>\n<div><img decoding=\"async\" class=\"post-images\" title=\"\" src=\"https:\/\/cdn.silicloud.com\/blog-img\/blog\/img\/657d086237434c4406be035f\/46-0.png\" alt=\"void, void, void, void, void, void, void, void, void, void, void, void...\" \/><\/p>\n<h2>[\u8ffd\u8a18] \u5728PHP\u4e2d\u6ca1\u6709void\u8f6c\u578b\/\u8fd0\u7b97\u7b26\u3002<\/p>\n<blockquote><p>\u6b64\u5916\uff0c\u67d0\u4e9b\u7f16\u7a0b\u8bed\u8a00\uff08\u5982JavaScript\uff09\u5b58\u5728void\u8fd0\u7b97\u7b26\u3002JavaScript\u7684void\u8fd0\u7b97\u7b26\u5bf9\u64cd\u4f5c\u6570\u7684\u8868\u8fbe\u5f0f\u8fdb\u884c\u6c42\u503c\u5e76\u5f97\u5230\u5176\u503c\uff0c\u4f46\u8be5\u503c\u4f1a\u88ab\u4e22\u5f03\uff0c\u4e0d\u8fd4\u56de\u4efb\u4f55\u503c\u3002\u8fd9\u7c7b\u4f3c\u4e8e\u5728C\u8bed\u8a00\u4e2d\u7528void\u7c7b\u578b\u8fdb\u884c\u5f3a\u5236\u8f6c\u6362\u6765\u660e\u786e\u4e22\u5f03\u503c\uff08\u4f8b\u5982\uff0c(void)printf(&#8220;Hello&#8221;)\uff09\u7684\u60c5\u51b5\u3002<\/p><\/blockquote>\n<p>\u5728PHP\u4e2d\uff0c\u6ca1\u6709\u9002\u7528\u4e8e\u8fd9\u79cd\u7528\u9014\u7684(void)\u9009\u9879\u3002\u53d6\u800c\u4ee3\u4e4b\u7684\u662f\uff0c\u5b58\u5728(unset)\u7c7b\u578b\u8f6c\u6362\u3002\u8fd9\u5c06\u5c06\u4efb\u4f55\u503c\u8f6c\u6362\u4e3anull\u3002<\/p>\n<pre class=\"post-pre\"><code><span class=\"nc\">Psy<\/span> <span class=\"nc\">Shell<\/span> <span class=\"n\">v0<\/span><span class=\"mf\">.8.17<\/span> <span class=\"p\">(<\/span><span class=\"no\">PHP<\/span> <span class=\"mf\">7.1.14<\/span> <span class=\"err\">\u2014<\/span> <span class=\"n\">cli<\/span><span class=\"p\">)<\/span> <span class=\"n\">by<\/span> <span class=\"nc\">Justin<\/span> <span class=\"nc\">Hileman<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"p\">(<\/span><span class=\"n\">unset<\/span><span class=\"p\">)[]<\/span>\r\n<span class=\"o\">=&gt;<\/span> <span class=\"kc\">null<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"p\">(<\/span><span class=\"n\">unset<\/span><span class=\"p\">)<\/span><span class=\"nb\">fopen<\/span><span class=\"p\">(<\/span><span class=\"s1\">'php:\/\/stdout'<\/span><span class=\"p\">,<\/span> <span class=\"s1\">'w'<\/span><span class=\"p\">);<\/span>\r\n<span class=\"o\">=&gt;<\/span> <span class=\"kc\">null<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"nv\">$a<\/span> <span class=\"o\">=<\/span> <span class=\"s2\">\"AAAAA\"<\/span><span class=\"p\">;<\/span>\r\n<span class=\"o\">=&gt;<\/span> <span class=\"s2\">\"AAAAA\"<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"p\">(<\/span><span class=\"n\">unset<\/span><span class=\"p\">)<\/span><span class=\"nv\">$a<\/span>\r\n<span class=\"o\">=&gt;<\/span> <span class=\"kc\">null<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"nv\">$a<\/span>\r\n<span class=\"o\">=&gt;<\/span> <span class=\"s2\">\"AAAAA\"<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"nb\">unset<\/span><span class=\"p\">(<\/span><span class=\"nv\">$a<\/span><span class=\"p\">)<\/span>\r\n<span class=\"o\">&gt;&gt;&gt;<\/span> <span class=\"nv\">$a<\/span>\r\n<span class=\"no\">PHP<\/span> <span class=\"nc\">Notice<\/span><span class=\"o\">:<\/span>  <span class=\"nc\">Undefined<\/span> <span class=\"n\">variable<\/span><span class=\"o\">:<\/span> <span class=\"n\">a<\/span> <span class=\"n\">on<\/span> <span class=\"n\">line<\/span> <span class=\"mi\">1<\/span>\r\n<\/code><\/pre>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c(unset)\u51fd\u6570\u4f1a\u65e0\u8bba\u4f20\u5165\u4ec0\u4e48\u503c\u90fd\u8fd4\u56denull\uff0c\u4f46\u5e76\u4e0d\u4f1a\u5c06\u53d8\u91cf\u6062\u590d\u4e3a\u672a\u5b9a\u4e49\u72b6\u6001\u3002\u800c\u662f\u4f7f\u7528unset($v)\u6765\u5b9e\u73b0\u3002<\/p>\n<p>\u8fd9\u6709\u4ec0\u4e48\u7ffb\u8bd1\u7684\u4ef7\u503c\u5462\uff1f\u76f4\u63a5\u5199null\u4e0d\u5c31\u884c\u4e86\u5417\uff1f\u4e3a\u4ec0\u4e48\u4f1a\u6709\u8fd9\u6837\u7684\u7c7b\u578b\u8f6c\u6362\uff1f<\/p>\n<p>\u597d\u5427\uff0c\u6211\u4e0d\u77e5\u9053&#8230;&#8230;\u4ee5\u524d\u6211\u8fd9\u6837\u62b1\u6028\u7684\u65f6\u5019\uff0c\u597d\u50cf\u6709\u4eba\u7ed9\u6211\u4e00\u4e2a\u4ee4\u4eba\u6ee1\u610f\u7684\u89e3\u91ca\uff0c\u4f46\u6211\u5df2\u7ecf\u4e0d\u8bb0\u5f97\u4e86\uff0c\u6240\u4ee5\u8fd9\u53ef\u80fd\u662f\u4e00\u4ef6\u65e0\u5173\u7d27\u8981\u7684\u4e8b\u60c5\u3002<\/p>\n<h2>\u6ce8\u91ca<\/p>\n<div>2017\u5e744\u67082\u65e519:51:47\u53d1\u5e03<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5728PHP\u7684\u4e0a\u4e0b\u6587\u4e2d\uff0c&#8221;void&#8221;\u4e00\u8bcd\u4ee5\u51e0\u79cd\u4e0d\u540c\u7684\u610f\u4e49\u88ab\u4f7f\u7528\u3002 \u7b80\u76f4void\u662f\u4ec0\u4e48\u610f\u601d  [&hellip;]<\/p>\n","protected":false},"author":12,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[227],"class_list":["post-30640","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-227"],"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>\u5728PHP\u4e2d\uff0cvoid\u662f\u4ec0\u4e48\u610f\u601d\uff1f - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"\u5173\u4e8e\u5728PHP\u4e2d\uff0cvoid\u662f\u4ec0\u4e48\u610f\u601d\uff1f\u7684\u6280\u672f\u6587\u7ae0\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" 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