{"id":157460,"date":"2023-03-03T13:18:40","date_gmt":"2023-03-03T05:18:40","guid":{"rendered":"http:\/\/www.idc.net\/help\/157460\/"},"modified":"2023-03-03T13:18:40","modified_gmt":"2023-03-03T05:18:40","slug":"%e6%b7%b1%e5%85%a5%e5%89%96%e6%9e%90linux-socket%e4%b8%ad%e7%9a%84recv%e5%87%bd%e6%95%b0-linux-socket-recv%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/idc.net\/help\/157460\/","title":{"rendered":"\u6df1\u5165\u5256\u6790Linux Socket\u4e2d\u7684recv\u51fd\u6570 (linux socket recv\u51fd\u6570)"},"content":{"rendered":"

\u5728Linux Socket\u7f16\u7a0b\u4e2d\uff0crecv\u51fd\u6570\u662f\u5176\u4e2d\u4e00\u4e2a\u6700\u5e38\u7528\u7684\u51fd\u6570\u4e4b\u4e00\u3002recv\u51fd\u6570\u7528\u4e8e\u5728socket\u4e0a\u63a5\u6536\u6570\u636e\uff0c\u5e76\u5c06\u63a5\u6536\u5230\u7684\u6570\u636e\u5b58\u50a8\u5728\u6307\u5b9a\u7684\u7f13\u51b2\u533a\u4e2d\u3002\u672c\u6587\u5c06\uff0c\u5305\u62ec\u51fd\u6570\u539f\u578b\u3001\u53c2\u6570\u3001\u8fd4\u56de\u503c\u53ca\u5176\u4f7f\u7528\u65b9\u6cd5\u7b49\u65b9\u9762\u7684\u5185\u5bb9\u3002<\/p>\n

\u4e00\u3001\u51fd\u6570\u539f\u578b<\/p>\n

\u4e0b\u9762\u662f\u4f4d\u4e8e\u5934\u6587\u4ef6\u4e2d\u7684recv\u51fd\u6570\u7684\u539f\u578b\uff1a<\/p>\n<\/p>\n

\u201c`c<\/p>\n

ssize_t recv(int sockfd, void *buf, size_t len, int flags);<\/p>\n

\u201c`<\/p>\n

recv\u51fd\u6570\u7684\u539f\u578b\u4e2d\u5305\u62ec4\u4e2a\u53c2\u6570\uff1a<\/p>\n

1. sockfd\uff1asocket\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u7528\u4e8e\u6307\u5b9a\u6211\u4eec\u8981\u63a5\u6536\u6570\u636e\u7684socket\u3002<\/p>\n

2. buf\uff1a\u6307\u5411\u63a5\u6536\u7f13\u51b2\u533a\u7684\u6307\u9488\uff0c\u7528\u4e8e\u5b58\u50a8\u63a5\u6536\u5230\u7684\u6570\u636e\u3002<\/p>\n

3. len\uff1a\u63a5\u6536\u7f13\u51b2\u533a\u957f\u5ea6\uff0c\u7528\u4e8e\u6307\u5b9a\u7f13\u51b2\u533a\u7684\u957f\u5ea6\u3002<\/p>\n

4. flags\uff1a\u63a5\u6536\u6d88\u606f\u7684\u6807\u5fd7\uff0c\u53ef\u4ee5\u9009\u62e9MSG_WTALL\u3001MSG_DONTWT\u7b49\u6807\u5fd7\u3002<\/p>\n

\u4e8c\u3001\u53c2\u6570\u8be6\u89e3<\/p>\n

1. sockfd<\/p>\n

sockfd\u662fsocket\u6587\u4ef6\u63cf\u8ff0\u7b26\uff0c\u7528\u4e8e\u6307\u5b9a\u6211\u4eec\u8981\u63a5\u6536\u6570\u636e\u7684socket\u3002\u8be5\u53c2\u6570\u901a\u5e38\u662f\u901a\u8fc7\u8c03\u7528socket\u51fd\u6570\u521b\u5efa\u7684\uff0c\u5e76\u4e14\u5728\u8c03\u7528recv\u51fd\u6570\u4e4b\u524d\u9700\u8981\u5148\u7528bind\u6216connect\u7ed1\u5b9a\u5230\u4e00\u4e2a\u672c\u5730\u7aef\u53e3\u4e0a\u3002<\/p>\n

2. buf<\/p>\n

buf\u662f\u6307\u5411\u63a5\u6536\u7f13\u51b2\u533a\u7684\u6307\u9488\uff0c\u7528\u4e8e\u5b58\u50a8\u63a5\u6536\u5230\u7684\u6570\u636e\u3002\u8be5\u6307\u9488\u5fc5\u987b\u6307\u5411\u4e00\u5757\u8db3\u591f\u5927\u7684\u5185\u5b58\u7a7a\u95f4\uff0c\u4ee5\u5b58\u50a8\u63a5\u6536\u5230\u7684\u6570\u636e\u3002\u53e6\u5916\uff0cbuf\u4e5f\u53ef\u4ee5\u662f\u4e00\u4e2a\u6307\u5411\u5e38\u91cf\u7684\u6307\u9488\uff0c\u4f46\u662f\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u7f13\u51b2\u533a\u4e2d\u7684\u6570\u636e\u5c06\u88ab\u4e22\u5f03\uff0c\u5e76\u4e14recv\u51fd\u6570\u5c06\u8fd4\u56de\u4e00\u4e2a\u9519\u8bef\u3002<\/p>\n

3. len<\/p>\n

len\u662f\u63a5\u6536\u7f13\u51b2\u533a\u957f\u5ea6\uff0c\u7528\u4e8e\u6307\u5b9a\u7f13\u51b2\u533a\u7684\u957f\u5ea6\u3002\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5982\u679c\u63a5\u6536\u5230\u7684\u6570\u636e\u957f\u5ea6\u8d85\u51fa\u4e86len\u6307\u5b9a\u7684\u957f\u5ea6\uff0c\u5219\u53ea\u4f1a\u63a5\u6536len\u4e2a\u5b57\u8282\u7684\u6570\u636e\uff0c\u5e76\u5c06\u8d85\u51fa\u7684\u6570\u636e\u4e22\u5f03\u3002<\/p>\n

4. flags<\/p>\n

flags\u53c2\u6570\u7528\u4e8e\u63a5\u6536\u6d88\u606f\u7684\u6807\u5fd7\u3002\u5b83\u53ef\u4ee5\u662f\u4ee5\u4e0b\u51e0\u4e2a\u6807\u5fd7\u7684\u7ec4\u5408\uff1a<\/p>\n

\u2013 MSG_WTALL<\/p>\n

\u8be5\u6807\u5fd7\u7528\u4e8e\u8981\u6c42recv\u51fd\u6570\u7b49\u5f85\u63a5\u6536\u5230len\u4e2a\u5b57\u8282\u7684\u5b8c\u6574\u6d88\u606f\u3002\u5982\u679c\u6570\u636e\u5305\u5927\u5c0f\u5c0f\u4e8elen\uff0c\u5219recv\u51fd\u6570\u5c06\u4e00\u76f4\u7b49\u5f85\uff0c\u76f4\u5230\u63a5\u6536\u5230\u5b8c\u6574\u7684\u6d88\u606f\u4e3a\u6b62\u3002<\/p>\n

\u2013 MSG_DONTWT<\/p>\n

\u8be5\u6807\u5fd7\u7528\u4e8e\u6307\u793arecv\u51fd\u6570\u4ee5\u975e\u963b\u585e\u65b9\u5f0f\u8fd0\u884c\u3002\u5982\u679c\u7f13\u51b2\u533a\u6ca1\u6709\u6570\u636e\u53ef\u8bfb\u53d6\uff0c\u5219\u51fd\u6570\u7acb\u5373\u8fd4\u56de\uff0c\u5e76\u8fd4\u56de\u4e00\u4e2aEAGN\u9519\u8bef\u7801\u3002<\/p>\n

\u2013 MSG_PEEK<\/p>\n

\u8be5\u6807\u5fd7\u7528\u4e8e\u5728\u63a5\u6536\u6570\u636e\u4e4b\u524d\uff0c\u5148\u5c06\u6570\u636e\u4ece\u7f13\u51b2\u533a\u4e2d\u67e5\u770b\u4e00\u904d\u3002\u8fd9\u6837\u53ef\u4ee5\u5728\u4e0d\u5b9e\u9645\u8bfb\u53d6\u6570\u636e\u7684\u60c5\u51b5\u4e0b\u67e5\u770b\u7f13\u51b2\u533a\u4e2d\u7684\u6570\u636e\u3002<\/p>\n

\u4e09\u3001\u8fd4\u56de\u503c\u8bf4\u660e<\/p>\n

recv\u51fd\u6570\u7684\u8fd4\u56de\u503c\u662f\u4e00\u4e2asigned ssize_t\u7c7b\u578b\u7684\u6574\u6570\uff0c\u5b83\u8868\u793a\u63a5\u6536\u5230\u7684\u5b57\u8282\u6570\u3002\u5982\u679c\u8be5\u51fd\u6570\u8fd4\u56de-1\uff0c\u5219\u8868\u793a\u51fd\u6570\u6267\u884c\u5931\u8d25\uff0c\u5e76\u4e14errno\u53d8\u91cf\u5c06\u5305\u542b\u4e00\u4e2a\u9519\u8bef\u7801\u3002\u5982\u679c\u8fd4\u56de0\uff0c\u8868\u793a\u8fdc\u7a0b\u4e3b\u673a\u5df2\u5173\u95ed\u8fde\u63a5\u3002<\/p>\n

\u56db\u3001\u4f7f\u7528\u65b9\u6cd5<\/p>\n

\u4f7f\u7528recv\u51fd\u6570\u63a5\u6536\u6570\u636e\u7684\u57fa\u672c\u6b65\u9aa4\u5982\u4e0b\uff1a<\/p>\n

1. \u521b\u5efasocket\uff1a\u901a\u8fc7\u8c03\u7528socket\u51fd\u6570\u521b\u5efa\u4e00\u4e2asocket\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002<\/p>\n

2. \u7ed1\u5b9asocket\uff1a\u901a\u8fc7\u8c03\u7528bind\u51fd\u6570\u5c06socket\u7ed1\u5b9a\u5230\u4e00\u4e2a\u672c\u5730\u7aef\u53e3\u4e0a\u3002<\/p>\n

3. \u76d1\u542c\u8fde\u63a5\uff1a\u901a\u8fc7\u8c03\u7528listen\u51fd\u6570\u76d1\u542c\u8fde\u63a5\u8bf7\u6c42\uff0c\u7b49\u5f85\u5ba2\u6237\u7aef\u53d1\u8d77\u8fde\u63a5\u8bf7\u6c42\u3002<\/p>\n

4. \u63a5\u53d7\u8fde\u63a5\uff1a\u901a\u8fc7\u8c03\u7528accept\u51fd\u6570\u63a5\u53d7\u5ba2\u6237\u7aef\u7684\u8fde\u63a5\u8bf7\u6c42\uff0c\u5e76\u628a\u5ba2\u6237\u7aef\u8fde\u63a5\u7684socket\u8fd4\u56de\u3002<\/p>\n

5. \u63a5\u6536\u6570\u636e\uff1a\u901a\u8fc7\u8c03\u7528recv\u51fd\u6570\u63a5\u6536\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u6570\u636e\uff0c\u5e76\u5c06\u63a5\u6536\u5230\u7684\u6570\u636e\u5b58\u50a8\u5230\u6307\u5b9a\u7684\u7f13\u51b2\u533a\u4e2d\u3002<\/p>\n

\u201c`c<\/p>\n

int server_sockfd, client_sockfd;<\/p>\n

struct sockaddr_in server_address, client_address;<\/p>\n

char buffer[1024];<\/p>\n

\/* Create new socket *\/<\/p>\n

server_sockfd = socket(AF_INET, SOCK_STREAM, 0);<\/p>\n

\/* Bind socket to a local address *\/<\/p>\n

memset(&server_address, 0, sizeof(struct sockaddr_in));<\/p>\n

server_address.sin_family = AF_INET;<\/p>\n

server_address.sin_addr.s_addr = INADDR_ANY;<\/p>\n

server_address.sin_port = htons(8000);<\/p>\n

bind(server_sockfd, (struct sockaddr *)&server_address, sizeof(struct sockaddr_in));<\/p>\n

\/* Listen for incoming connections *\/<\/p>\n

listen(server_sockfd, 5);<\/p>\n

\/* Accept a connection *\/<\/p>\n

int client_len = sizeof(struct sockaddr_in);<\/p>\n

client_sockfd = accept(server_sockfd, (struct sockaddr *)&client_address, &client_len);<\/p>\n

\/* Receive data from client *\/<\/p>\n

memset(buffer, 0, sizeof(buffer));<\/p>\n

int nbytes = recv(client_sockfd, buffer, sizeof(buffer), 0);<\/p>\n

printf(\u201cReceived %d bytes: %s\\n\u201d, nbytes, buffer);<\/p>\n

\/* Close the socket *\/<\/p>\n

close(client_sockfd);<\/p>\n

close(server_sockfd);<\/p>\n

\u201c`<\/p>\n

\u4e0a\u8ff0\u4ee3\u7801\u6f14\u793a\u4e86\u4e00\u4e2a\u7b80\u5355\u7684socket\u6570\u636e\u63a5\u6536\u4f8b\u5b50\u3002\u9996\u5148\u4f7f\u7528socket\u51fd\u6570\u521b\u5efa\u4e86\u4e00\u4e2a\u65b0\u7684socket\uff0c\u7136\u540e\u901a\u8fc7bind\u51fd\u6570\u5c06\u8be5socket\u7ed1\u5b9a\u5230\u672c\u57308000\u7aef\u53e3\u4e0a\u3002\u63a5\u4e0b\u6765\u4f7f\u7528listen\u51fd\u6570\u76d1\u542c\u8be5socket\u4e0a\u7684\u8fde\u63a5\u8bf7\u6c42\u3002<\/p>\n

\u5f53\u6709\u5ba2\u6237\u7aef\u53d1\u8d77\u8fde\u63a5\u8bf7\u6c42\u540e\uff0c\u4f7f\u7528accept\u51fd\u6570\u63a5\u53d7\u8be5\u8fde\u63a5\u8bf7\u6c42\uff0c\u5e76\u8fd4\u56de\u5ba2\u6237\u7aef\u8fde\u63a5\u7684socket\u6587\u4ef6\u63cf\u8ff0\u7b26\u3002\u6700\u540e\u4f7f\u7528recv\u51fd\u6570\u63a5\u6536\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u6570\u636e\uff0c\u5e76\u5c06\u63a5\u6536\u5230\u7684\u6570\u636e\u5b58\u50a8\u5230\u6307\u5b9a\u7684\u7f13\u51b2\u533a\u4e2d\u3002<\/p>\n

\u5728\u63a5\u6536\u6570\u636e\u540e\uff0c\u53ef\u4ee5\u6839\u636e\u5b9e\u9645\u60c5\u51b5\u8fdb\u884c\u5904\u7406\u3002\u6700\u540e\u518d\u5173\u95edsocket\uff0c\u91ca\u653e\u8d44\u6e90\u3002<\/p>\n

recv\u51fd\u6570\u662fLinux Socket\u7f16\u7a0b\u4e2d\u6700\u5e38\u7528\u7684\u51fd\u6570\u4e4b\u4e00\uff0c\u5b83\u7528\u4e8e\u5728socket\u4e0a\u63a5\u6536\u6570\u636e\uff0c\u5e76\u5c06\u63a5\u6536\u5230\u7684\u6570\u636e\u5b58\u50a8\u5728\u6307\u5b9a\u7684\u7f13\u51b2\u533a\u4e2d\u3002\u5728\u4f7f\u7528\u8be5\u51fd\u6570\u65f6\uff0c\u9700\u8981\u6307\u5b9asocket\u6587\u4ef6\u63cf\u8ff0\u7b26\u3001\u63a5\u6536\u7f13\u51b2\u533a\u3001\u7f13\u51b2\u533a\u957f\u5ea6\u548c\u6807\u5fd7\u7b49\u53c2\u6570\u3002<\/p>\n

\u5728\u4f7f\u7528recv\u51fd\u6570\u65f6\uff0c\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n

1. \u63a5\u6536\u7f13\u51b2\u533a\u5fc5\u987b\u8db3\u591f\u5927\uff0c\u4ee5\u5b58\u50a8\u63a5\u6536\u5230\u7684\u6570\u636e\u3002<\/p>\n

2. \u63a5\u6536\u51fd\u6570\u53ef\u80fd\u4f1a\u88ab\u963b\u585e\uff0c\u5982\u679c\u9700\u8981\u975e\u963b\u585e\u65b9\u5f0f\u8fd0\u884c\uff0c\u5219\u53ef\u4ee5\u4f7f\u7528MSG_DONTWT\u6807\u5fd7\u3002<\/p>\n

3. \u63a5\u6536\u51fd\u6570\u63a5\u6536\u5230\u7684\u6570\u636e\u53ef\u80fd\u8d85\u51fa\u6307\u5b9a\u7684\u7f13\u51b2\u533a\u957f\u5ea6\uff0c\u9700\u8981\u6ce8\u610f\u5904\u7406\u6570\u636e\u6ea2\u51fa\u7684\u60c5\u51b5\u3002<\/p>\n

\u76f8\u5173\u95ee\u9898\u62d3\u5c55\u9605\u8bfb\uff1a<\/strong><\/p>\n