unix域套接字UDP网络编程,服务器如下面：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>#define SA struct sockaddr
#define PATHNAME "/tmp/unixudp"void err_sys(const char *errmsg);int main(void)
{int sockfd;struct sockaddr_un servaddr, cliaddr;char buf[BUFSIZ];ssize_t n;socklen_t len = sizeof(cliaddr);if ((sockfd = socket(AF_LOCAL, SOCK_DGRAM, 0)) == -1)err_sys("socket");bzero(&servaddr, sizeof(servaddr));unlink(PATHNAME);servaddr.sun_family = AF_LOCAL;strncpy(servaddr.sun_path, PATHNAME, sizeof(servaddr.sun_path) - 1);if (bind(sockfd, (SA *)&servaddr, sizeof(servaddr)) == -1)err_sys("bind");for(;;){n = recvfrom(sockfd, buf, sizeof(buf), 0, (SA *)&cliaddr, &len);if (n == -1)err_sys("recvfrom");elseprintf("%s\n", buf);if (sendto(sockfd, buf, n, 0, (SA *)&cliaddr, sizeof(cliaddr)) != n)err_sys("sendto");}exit(0);
}void err_sys(const char *errmsg)
{perror(errmsg);exit(1);
}

client程序：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>#define SA struct sockaddr
#define PATHNAME "/tmp/unixudp"void err_sys(const char *errmsg);int main(void)
{int sockfd;struct sockaddr_un servaddr, localaddr;char buf[BUFSIZ], s[] = "hello china";ssize_t n;if ((sockfd = socket(AF_LOCAL, SOCK_DGRAM, 0)) == -1)err_sys("socket");bzero(&localaddr, sizeof(localaddr));localaddr.sun_family = AF_LOCAL;strncpy(localaddr.sun_path, tmpnam(NULL), sizeof(localaddr.sun_path) - 1);if (bind(sockfd, (SA *)&localaddr, sizeof(localaddr)) == -1)err_sys("bind");bzero(&servaddr, sizeof(servaddr));servaddr.sun_family = AF_LOCAL;strncpy(servaddr.sun_path, PATHNAME, sizeof(servaddr.sun_path) - 1);for(;;){if (sendto(sockfd, s, strlen(s), 0, (SA *)&servaddr, sizeof(servaddr)) == -1)err_sys("sendto");if ((n = read(sockfd, buf, sizeof(buf))) == -1)err_sys("read");else printf("%s\n", buf);usleep((rand() % 10) * 10000);}exit(0);
}void err_sys(const char *errmsg)
{perror(errmsg);exit(1);
}