{"id":375,"date":"2026-05-02T23:17:12","date_gmt":"2026-05-02T15:17:12","guid":{"rendered":"http:\/\/www.millscience.cn\/?p=375"},"modified":"2026-05-02T23:17:16","modified_gmt":"2026-05-02T15:17:16","slug":"udpbroadcast","status":"publish","type":"post","link":"https:\/\/www.millscience.cn\/index.php\/udpbroadcast\/","title":{"rendered":"\u8bbe\u7f6eUDP\u7684\u5e7f\u64ad\u5c5e\u6027"},"content":{"rendered":"\n<div class=\"wp-block-kevinbatdorf-code-block-pro cbp-has-line-numbers\" data-code-block-pro-font-family=\"Code-Pro-JetBrains-Mono\" style=\"font-size:.875rem;font-family:Code-Pro-JetBrains-Mono,ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;--cbp-line-number-color:#D4D4D4;--cbp-line-number-width:calc(2 * 0.6 * .875rem);line-height:1.25rem;--cbp-tab-width:2;tab-size:var(--cbp-tab-width, 2)\"><span style=\"display:block;padding:16px 0 0 16px;margin-bottom:-1px;width:100%;text-align:left;background-color:#1E1E1E\"><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"54\" height=\"14\" viewBox=\"0 0 54 14\"><g fill=\"none\" fill-rule=\"evenodd\" transform=\"translate(1 1)\"><circle cx=\"6\" cy=\"6\" r=\"6\" fill=\"#FF5F56\" stroke=\"#E0443E\" stroke-width=\".5\"><\/circle><circle cx=\"26\" cy=\"6\" r=\"6\" fill=\"#FFBD2E\" stroke=\"#DEA123\" stroke-width=\".5\"><\/circle><circle cx=\"46\" cy=\"6\" r=\"6\" fill=\"#27C93F\" stroke=\"#1AAB29\" stroke-width=\".5\"><\/circle><\/g><\/svg><\/span><span role=\"button\" tabindex=\"0\" style=\"color:#D4D4D4;display:none\" aria-label=\"\u590d\u5236\" class=\"code-block-pro-copy-button\"><pre class=\"code-block-pro-copy-button-pre\" aria-hidden=\"true\"><textarea class=\"code-block-pro-copy-button-textarea\" tabindex=\"-1\" aria-hidden=\"true\" readonly>\/**\n * @filename:    UDP_BROADCAST.c\n * @brief:       UDP_BROADCAST\n * @author:      philia\n * @date:        2026\/4\/19\n * @version:     ver1.0\n * @note         NONE\n * CopyRight (c) 2026   philia  All Right Reseverd\n *\/\n\n#include &lt;stdio.h>\n#include &lt;sys\/types.h> \/* See NOTES *\/\n#include &lt;sys\/socket.h>\n#include &lt;netinet\/ip.h> \/* superset of previous *\/\n#include &lt;arpa\/inet.h>\n#include &lt;errno.h>\n#include &lt;string.h>\n#include &lt;stdlib.h>\n#include &lt;pthread.h>\n\nint udp_socket;\n\nint main(int argc, const char *argv[])\n{\n\n    \/\/ \u521b\u5efa\u5957\u63a5\u5b57\u6587\u4ef6\n    udp_socket = socket(AF_INET, SOCK_DGRAM, 0);\n    if (udp_socket == -1)\n    {\n        fprintf(stderr, \"udp_socket error, errno:%d,%s\", errno, strerror(errno));\n        exit(-1);\n    }\n\n    int flag = -1;\n    int size = 4;\n\n    \/\/ \u83b7\u53d6\u5f53\u524d\u7684\u5e7f\u64ad\u5c5e\u6027\n    getsockopt(udp_socket, SOL_SOCKET, SO_BROADCAST,\n               (void *)&amp;flag, &amp;size);\n\n    printf(\"%d\\n\", flag);\n\n    int optval = 1;\n    \/\/ \u8bbe\u7f6e\u5e7f\u64ad\u5c5e\u6027\n    setsockopt(udp_socket, SOL_SOCKET, SO_BROADCAST,\n               &amp;optval, 4);\n\n    \/\/ \u518d\u6b21\u83b7\u53d6\u5f53\u524d\u7684\u5e7f\u64ad\u5c5e\u6027\n    getsockopt(udp_socket, SOL_SOCKET, SO_BROADCAST,\n               (void *)&amp;flag, &amp;size);\n\n    printf(\"%d\\n\", flag);\n    return 0;\n}<\/textarea><\/pre><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" style=\"width:24px;height:24px\" fill=\"none\" viewBox=\"0 0 24 24\" stroke=\"currentColor\" stroke-width=\"2\"><path class=\"with-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M4.5 12.75l6 6 9-13.5\"><\/path><path class=\"without-check\" stroke-linecap=\"round\" stroke-linejoin=\"round\" d=\"M16.5 8.25V6a2.25 2.25 0 00-2.25-2.25H6A2.25 2.25 0 003.75 6v8.25A2.25 2.25 0 006 16.5h2.25m8.25-8.25H18a2.25 2.25 0 012.25 2.25V18A2.25 2.25 0 0118 20.25h-7.5A2.25 2.25 0 018.25 18v-1.5m8.25-8.25h-6a2.25 2.25 0 00-2.25 2.25v6\"><\/path><\/svg><\/span><pre class=\"shiki dark-plus\" style=\"background-color: #1E1E1E\" tabindex=\"0\"><code><span class=\"line\"><span style=\"color: #6A9955\">\/**<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * <\/span><span style=\"color: #569CD6\">@filename:<\/span><span style=\"color: #6A9955\">    UDP_BROADCAST.c<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * <\/span><span style=\"color: #569CD6\">@brief<\/span><span style=\"color: #6A9955\">:       UDP_BROADCAST<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * <\/span><span style=\"color: #569CD6\">@author<\/span><span style=\"color: #6A9955\">:      philia<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * <\/span><span style=\"color: #569CD6\">@date<\/span><span style=\"color: #6A9955\">:        2026\/4\/19<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * <\/span><span style=\"color: #569CD6\">@version<\/span><span style=\"color: #6A9955\">:     ver1.0<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * <\/span><span style=\"color: #569CD6\">@note<\/span><span style=\"color: #6A9955\">         NONE<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> * CopyRight (c) 2026   philia  All Right Reseverd<\/span><\/span>\n<span class=\"line\"><span style=\"color: #6A9955\"> *\/<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;stdio.h&gt;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;sys\/types.h&gt;<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #6A9955\">\/* See NOTES *\/<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;sys\/socket.h&gt;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;netinet\/ip.h&gt;<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #6A9955\">\/* superset of previous *\/<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;arpa\/inet.h&gt;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;errno.h&gt;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;string.h&gt;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;stdlib.h&gt;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #C586C0\">#include<\/span><span style=\"color: #569CD6\"> <\/span><span style=\"color: #CE9178\">&lt;pthread.h&gt;<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #569CD6\">int<\/span><span style=\"color: #D4D4D4\"> udp_socket;<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #569CD6\">int<\/span><span style=\"color: #D4D4D4\"> <\/span><span style=\"color: #DCDCAA\">main<\/span><span style=\"color: #D4D4D4\">(<\/span><span style=\"color: #569CD6\">int<\/span><span style=\"color: #D4D4D4\"> <\/span><span style=\"color: #9CDCFE\">argc<\/span><span style=\"color: #D4D4D4\">, <\/span><span style=\"color: #569CD6\">const<\/span><span style=\"color: #D4D4D4\"> <\/span><span style=\"color: #569CD6\">char<\/span><span style=\"color: #D4D4D4\"> *<\/span><span style=\"color: #9CDCFE\">argv<\/span><span style=\"color: #569CD6\">[]<\/span><span style=\"color: #D4D4D4\">)<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">{<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #6A9955\">\/\/ \u521b\u5efa\u5957\u63a5\u5b57\u6587\u4ef6<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    udp_socket = <\/span><span style=\"color: #DCDCAA\">socket<\/span><span style=\"color: #D4D4D4\">(AF_INET, SOCK_DGRAM, <\/span><span style=\"color: #B5CEA8\">0<\/span><span style=\"color: #D4D4D4\">);<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #C586C0\">if<\/span><span style=\"color: #D4D4D4\"> (udp_socket == -<\/span><span style=\"color: #B5CEA8\">1<\/span><span style=\"color: #D4D4D4\">)<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    {<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">        <\/span><span style=\"color: #DCDCAA\">fprintf<\/span><span style=\"color: #D4D4D4\">(stderr, <\/span><span style=\"color: #CE9178\">&quot;udp_socket error, errno:<\/span><span style=\"color: #9CDCFE\">%d<\/span><span style=\"color: #CE9178\">,<\/span><span style=\"color: #9CDCFE\">%s<\/span><span style=\"color: #CE9178\">&quot;<\/span><span style=\"color: #D4D4D4\">, errno, <\/span><span style=\"color: #DCDCAA\">strerror<\/span><span style=\"color: #D4D4D4\">(errno));<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">        <\/span><span style=\"color: #DCDCAA\">exit<\/span><span style=\"color: #D4D4D4\">(-<\/span><span style=\"color: #B5CEA8\">1<\/span><span style=\"color: #D4D4D4\">);<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    }<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #569CD6\">int<\/span><span style=\"color: #D4D4D4\"> flag = -<\/span><span style=\"color: #B5CEA8\">1<\/span><span style=\"color: #D4D4D4\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #569CD6\">int<\/span><span style=\"color: #D4D4D4\"> size = <\/span><span style=\"color: #B5CEA8\">4<\/span><span style=\"color: #D4D4D4\">;<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #6A9955\">\/\/ \u83b7\u53d6\u5f53\u524d\u7684\u5e7f\u64ad\u5c5e\u6027<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #DCDCAA\">getsockopt<\/span><span style=\"color: #D4D4D4\">(udp_socket, SOL_SOCKET, SO_BROADCAST,<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">               (<\/span><span style=\"color: #569CD6\">void<\/span><span style=\"color: #D4D4D4\"> *)&amp;flag, &amp;size);<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #DCDCAA\">printf<\/span><span style=\"color: #D4D4D4\">(<\/span><span style=\"color: #CE9178\">&quot;<\/span><span style=\"color: #9CDCFE\">%d<\/span><span style=\"color: #D7BA7D\">\\n<\/span><span style=\"color: #CE9178\">&quot;<\/span><span style=\"color: #D4D4D4\">, flag);<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #569CD6\">int<\/span><span style=\"color: #D4D4D4\"> optval = <\/span><span style=\"color: #B5CEA8\">1<\/span><span style=\"color: #D4D4D4\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #6A9955\">\/\/ \u8bbe\u7f6e\u5e7f\u64ad\u5c5e\u6027<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #DCDCAA\">setsockopt<\/span><span style=\"color: #D4D4D4\">(udp_socket, SOL_SOCKET, SO_BROADCAST,<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">               &amp;optval, <\/span><span style=\"color: #B5CEA8\">4<\/span><span style=\"color: #D4D4D4\">);<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #6A9955\">\/\/ \u518d\u6b21\u83b7\u53d6\u5f53\u524d\u7684\u5e7f\u64ad\u5c5e\u6027<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #DCDCAA\">getsockopt<\/span><span style=\"color: #D4D4D4\">(udp_socket, SOL_SOCKET, SO_BROADCAST,<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">               (<\/span><span style=\"color: #569CD6\">void<\/span><span style=\"color: #D4D4D4\"> *)&amp;flag, &amp;size);<\/span><\/span>\n<span class=\"line\"><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #DCDCAA\">printf<\/span><span style=\"color: #D4D4D4\">(<\/span><span style=\"color: #CE9178\">&quot;<\/span><span style=\"color: #9CDCFE\">%d<\/span><span style=\"color: #D7BA7D\">\\n<\/span><span style=\"color: #CE9178\">&quot;<\/span><span style=\"color: #D4D4D4\">, flag);<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">    <\/span><span style=\"color: #C586C0\">return<\/span><span style=\"color: #D4D4D4\"> <\/span><span style=\"color: #B5CEA8\">0<\/span><span style=\"color: #D4D4D4\">;<\/span><\/span>\n<span class=\"line\"><span style=\"color: #D4D4D4\">}<\/span><\/span><\/code><\/pre><\/div>\n","protected":false},"excerpt":{"rendered":"","protected":false},"author":1,"featured_media":376,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19,13],"tags":[],"class_list":["post-375","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-embedded","category-learning"],"_links":{"self":[{"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/posts\/375","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/comments?post=375"}],"version-history":[{"count":1,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/posts\/375\/revisions"}],"predecessor-version":[{"id":377,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/posts\/375\/revisions\/377"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/media\/376"}],"wp:attachment":[{"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/media?parent=375"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/categories?post=375"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.millscience.cn\/index.php\/wp-json\/wp\/v2\/tags?post=375"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}