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");

        else

            printf("%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);

}