`getsockopt()` in Linux is a system call function used to retrieve the value of socket options. Its prototype is as follows:<\/p>\n
#include <sys\/socket.h><\/p>
int getsockopt(int sockfd, int level, int optname, void *optval, socklen_t *optlen);<\/p><\/pre>\n
The meanings of the parameters are as follows:<\/p>\n
sockfd\uff1a\u5957\u63a5\u5b57\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u6307\u5b9a\u8981\u83b7\u53d6\u9009\u9879\u7684\u5957\u63a5\u5b57\u3002<\/p>
level\uff1a\u9009\u9879\u6240\u5c5e\u7684\u534f\u8bae\u5c42\u7ea7\uff0c\u5e38\u89c1\u7684\u503c\u6709 SOL_SOCKET\uff08\u901a\u7528\u5957\u63a5\u5b57\u9009\u9879\uff09\u548c IPPROTO_TCP\uff08TCP\u534f\u8bae\u9009\u9879\uff09\u7b49\u3002<\/p>
optname\uff1a\u9009\u9879\u7684\u540d\u79f0\uff0c\u8868\u793a\u60a8\u8981\u83b7\u53d6\u7684\u5177\u4f53\u9009\u9879\u3002<\/p>
optval\uff1a\u6307\u5411\u5b58\u50a8\u9009\u9879\u503c\u7684\u7f13\u51b2\u533a\u7684\u6307\u9488\u3002<\/p>
optlen\uff1a\u6307\u5411\u4e00\u4e2a\u6574\u6570\u7684\u6307\u9488\uff0c\u7528\u4e8e\u6307\u5b9a\u7f13\u51b2\u533a\u7684\u5927\u5c0f\uff0c\u5e76\u8fd4\u56de\u5b9e\u9645\u9009\u9879\u6570\u636e\u7684\u957f\u5ea6\u3002<\/p><\/pre>\n
The function `getsockopt()` retrieves the current value of the corresponding option by passing the `sockfd`, `level`, and `optname` parameters, and stores it in the buffer specified by `optval`. Upon successful call, it will return 0; otherwise, it returns -1 and sets the corresponding error code.<\/p>\n
Here is a simple example of how to use it:<\/p>\n
#include <stdio.h><\/p>
#include <stdlib.h><\/p>
#include <sys\/socket.h><\/p>
int main() {<\/p>
int sockfd = socket(AF_INET, SOCK_STREAM, 0);<\/p>
if (sockfd == -1) {<\/p>
perror(\"socket\");<\/p>
exit(1);<\/p>
}<\/p>
int option;<\/p>
socklen_t option_len = sizeof(option);<\/p>
\/\/ \u83b7\u53d6\u5957\u63a5\u5b57\u7684 SO_REUSEADDR \u9009\u9879\u503c<\/p>
if (getsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &option, &option_len) == -1) {<\/p>
perror(\"getsockopt\");<\/p>
exit(1);<\/p>
}<\/p>
printf(\"SO_REUSEADDR: %d\\n\", option);<\/p>
close(sockfd);<\/p>
return 0;<\/p>
}<\/p><\/pre>\n
The sample code here creates a socket and uses the `getsockopt()` function to obtain the current value of the `SO_REUSEADDR` option. The value is then printed out for your reference. Make adjustments based on your specific needs and option names.<\/p>\n","protected":false},"excerpt":{"rendered":"
`getsockopt()` in Linux is a system call function used to retrieve the value of socket options. Its prototype is as follows: #include <sys\/socket.h>int getsockopt(int sockfd, int level, int optname, void *optval, socklen_t *optlen); The meanings of the parameters are as follows: sockfd\uff1a\u5957\u63a5\u5b57\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u6307\u5b9a\u8981\u83b7\u53d6\u9009\u9879\u7684\u5957\u63a5\u5b57\u3002level\uff1a\u9009\u9879\u6240\u5c5e\u7684\u534f\u8bae\u5c42\u7ea7\uff0c\u5e38\u89c1\u7684\u503c\u6709 SOL_SOCKET\uff08\u901a\u7528\u5957\u63a5\u5b57\u9009\u9879\uff09\u548c IPPROTO_TCP\uff08TCP\u534f\u8bae\u9009\u9879\uff09\u7b49\u3002optname\uff1a\u9009\u9879\u7684\u540d\u79f0\uff0c\u8868\u793a\u60a8\u8981\u83b7\u53d6\u7684\u5177\u4f53\u9009\u9879\u3002optval\uff1a\u6307\u5411\u5b58\u50a8\u9009\u9879\u503c\u7684\u7f13\u51b2\u533a\u7684\u6307\u9488\u3002optlen\uff1a\u6307\u5411\u4e00\u4e2a\u6574\u6570\u7684\u6307\u9488\uff0c\u7528\u4e8e\u6307\u5b9a\u7f13\u51b2\u533a\u7684\u5927\u5c0f\uff0c\u5e76\u8fd4\u56de\u5b9e\u9645\u9009\u9879\u6570\u636e\u7684\u957f\u5ea6\u3002 The function `getsockopt()` retrieves the current value of the corresponding option by passing the `sockfd`, `level`, and `optname` parameters, and stores it in the […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[],"class_list":["post-27398","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"yoast_head":"\n
What is the usage of getsockopt in Linux? - Blog - Silicon Cloud<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What is the usage of getsockopt in Linux?\" \/>\n<meta property=\"og:description\" content=\"`getsockopt()` in Linux is a system call function used to retrieve the value of socket options. Its prototype is as follows: #include <sys\/socket.h>int getsockopt(int sockfd, int level, int optname, void *optval, socklen_t *optlen); The meanings of the parameters are as follows: sockfd\uff1a\u5957\u63a5\u5b57\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u6307\u5b9a\u8981\u83b7\u53d6\u9009\u9879\u7684\u5957\u63a5\u5b57\u3002level\uff1a\u9009\u9879\u6240\u5c5e\u7684\u534f\u8bae\u5c42\u7ea7\uff0c\u5e38\u89c1\u7684\u503c\u6709 SOL_SOCKET\uff08\u901a\u7528\u5957\u63a5\u5b57\u9009\u9879\uff09\u548c IPPROTO_TCP\uff08TCP\u534f\u8bae\u9009\u9879\uff09\u7b49\u3002optname\uff1a\u9009\u9879\u7684\u540d\u79f0\uff0c\u8868\u793a\u60a8\u8981\u83b7\u53d6\u7684\u5177\u4f53\u9009\u9879\u3002optval\uff1a\u6307\u5411\u5b58\u50a8\u9009\u9879\u503c\u7684\u7f13\u51b2\u533a\u7684\u6307\u9488\u3002optlen\uff1a\u6307\u5411\u4e00\u4e2a\u6574\u6570\u7684\u6307\u9488\uff0c\u7528\u4e8e\u6307\u5b9a\u7f13\u51b2\u533a\u7684\u5927\u5c0f\uff0c\u5e76\u8fd4\u56de\u5b9e\u9645\u9009\u9879\u6570\u636e\u7684\u957f\u5ea6\u3002 The function `getsockopt()` retrieves the current value of the corresponding option by passing the `sockfd`, `level`, and `optname` parameters, and stores it in the […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/\" \/>\n<meta property=\"og:site_name\" content=\"Blog - Silicon Cloud\" \/>\n<meta property=\"article:publisher\" content=\"https:\/\/www.facebook.com\/SiliCloudGlobal\/\" \/>\n<meta property=\"article:published_time\" content=\"2024-03-16T08:25:03+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2024-03-22T10:56:29+00:00\" \/>\n<meta name=\"author\" content=\"Olivia Parker\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:creator\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:site\" content=\"@SiliCloudGlobal\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Olivia Parker\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/#article\",\"isPartOf\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/\"},\"author\":{\"name\":\"Olivia Parker\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/#\/schema\/person\/3ff7b3da0e45ac5dbbef2502f3cea8d9\"},\"headline\":\"What is the usage of getsockopt in Linux?\",\"datePublished\":\"2024-03-16T08:25:03+00:00\",\"dateModified\":\"2024-03-22T10:56:29+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/\"},\"wordCount\":132,\"commentCount\":0,\"publisher\":{\"@id\":\"https:\/\/www.silicloud.com\/blog\/#organization\"},\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/\",\"url\":\"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/\",\"name\":\"What is the usage of getsockopt in Linux? 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Its prototype is as follows: #include <sys\/socket.h>int getsockopt(int sockfd, int level, int optname, void *optval, socklen_t *optlen); The meanings of the parameters are as follows: sockfd\uff1a\u5957\u63a5\u5b57\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u6307\u5b9a\u8981\u83b7\u53d6\u9009\u9879\u7684\u5957\u63a5\u5b57\u3002level\uff1a\u9009\u9879\u6240\u5c5e\u7684\u534f\u8bae\u5c42\u7ea7\uff0c\u5e38\u89c1\u7684\u503c\u6709 SOL_SOCKET\uff08\u901a\u7528\u5957\u63a5\u5b57\u9009\u9879\uff09\u548c IPPROTO_TCP\uff08TCP\u534f\u8bae\u9009\u9879\uff09\u7b49\u3002optname\uff1a\u9009\u9879\u7684\u540d\u79f0\uff0c\u8868\u793a\u60a8\u8981\u83b7\u53d6\u7684\u5177\u4f53\u9009\u9879\u3002optval\uff1a\u6307\u5411\u5b58\u50a8\u9009\u9879\u503c\u7684\u7f13\u51b2\u533a\u7684\u6307\u9488\u3002optlen\uff1a\u6307\u5411\u4e00\u4e2a\u6574\u6570\u7684\u6307\u9488\uff0c\u7528\u4e8e\u6307\u5b9a\u7f13\u51b2\u533a\u7684\u5927\u5c0f\uff0c\u5e76\u8fd4\u56de\u5b9e\u9645\u9009\u9879\u6570\u636e\u7684\u957f\u5ea6\u3002 The function `getsockopt()` retrieves the current value of the corresponding option by passing the `sockfd`, `level`, and `optname` parameters, and stores it in the […]","og_url":"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/","og_site_name":"Blog - Silicon Cloud","article_publisher":"https:\/\/www.facebook.com\/SiliCloudGlobal\/","article_published_time":"2024-03-16T08:25:03+00:00","article_modified_time":"2024-03-22T10:56:29+00:00","author":"Olivia Parker","twitter_card":"summary_large_image","twitter_creator":"@SiliCloudGlobal","twitter_site":"@SiliCloudGlobal","twitter_misc":{"Written by":"Olivia Parker","Est. reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/#article","isPartOf":{"@id":"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/"},"author":{"name":"Olivia Parker","@id":"https:\/\/www.silicloud.com\/blog\/#\/schema\/person\/3ff7b3da0e45ac5dbbef2502f3cea8d9"},"headline":"What is the usage of getsockopt in Linux?","datePublished":"2024-03-16T08:25:03+00:00","dateModified":"2024-03-22T10:56:29+00:00","mainEntityOfPage":{"@id":"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/"},"wordCount":132,"commentCount":0,"publisher":{"@id":"https:\/\/www.silicloud.com\/blog\/#organization"},"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/","url":"https:\/\/www.silicloud.com\/blog\/what-is-the-usage-of-getsockopt-in-linux\/","name":"What is the usage of getsockopt in Linux? 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