转载
注意事项，端口号对应，
server端代码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<unistd.h>

#define MAXLINE 4096

int main(int argc, char **argv) {
    int listenfd, connfd;
    struct sockaddr_in servaddr;
    char buff[4096];
    int n;

    if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
        printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
        return 0;
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(8888);

    if (bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) == -1) {
        printf("bind socket error: %s(errno: %d)\n", strerror(errno), errno);
        return 0;
    }

    if (listen(listenfd, 10) == -1) {
        printf("listen socket error: %s(errno: %d)\n", strerror(errno), errno);
        return 0;
    }

    printf("======waiting for client's request======\n");
    while (1) {
        if ((connfd = accept(listenfd, (struct sockaddr *) NULL, NULL)) == -1) {
            printf("accept socket error: %s(errno: %d)", strerror(errno), errno);
            continue;
        }
        n = recv(connfd, buff, MAXLINE, 0);
        buff[n] = '\0';
        printf("recv msg from client: %s\n", buff);
        close(connfd);
    }
    close(listenfd);
    return 0;
}

clietn端代码

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<errno.h>
#include<sys/types.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<unistd.h>

#define MAXLINE 4096

int main(int argc, char **argv) {
    int sockfd, n;
    char recvline[4096], sendline[4096];
    struct sockaddr_in servaddr;

    if (argc != 2) {
        printf("usage: ./client <ipaddress>\n");
        return 0;
    }

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
        printf("create socket error: %s(errno: %d)\n", strerror(errno), errno);
        return 0;
    }

    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(8888);
    if (inet_pton(AF_INET, argv[1], &servaddr.sin_addr) <= 0) {
        printf("inet_pton error for %s\n", argv[1]);
        return 0;
    }

    if (connect(sockfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0) {
        printf("connect error: %s(errno: %d)\n", strerror(errno), errno);
        return 0;
    }

    printf("send msg to server: \n");
    fgets(sendline, 4096, stdin);
    if (send(sockfd, sendline, strlen(sendline), 0) < 0) {
        printf("send msg error: %s(errno: %d)\n", strerror(errno), errno);
        return 0;
    }
    close(sockfd);
    return 0;
}

运行例子

cai@caia:~/CLionProjects/study_opencvcc/build$ ./socket_server 
======waiting for client's request======
recv msg from client: ssssss

recv msg from client: eeee

cai@caia:~/CLionProjects/study_opencvcc/build$ ./socket_clent 127.0.0.1
send msg to server: 
ssssss
cai@caia:~/CLionProjects/study_opencvcc/build$ ./socket_clent 127.0.0.1
send msg to server: 
eeee
cai@caia:~/CLionProjects/study_opencvcc/build$ 

socket.h相关函数参考

int     accept(int, struct sockaddr *restrict, socklen_t *restrict);
int     bind(int, const struct sockaddr *, socklen_t);
int     connect(int, const struct sockaddr *, socklen_t);
int     getpeername(int, struct sockaddr *restrict, socklen_t *restrict);
int     getsockname(int, struct sockaddr *restrict, socklen_t *restrict);
int     getsockopt(int, int, int, void *restrict, socklen_t *restrict);
int     listen(int, int);
ssize_t recv(int, void *, size_t, int);
ssize_t recvfrom(int, void *restrict, size_t, int,
        struct sockaddr *restrict, socklen_t *restrict);
ssize_t recvmsg(int, struct msghdr *, int);
ssize_t send(int, const void *, size_t, int);
ssize_t sendmsg(int, const struct msghdr *, int);
ssize_t sendto(int, const void *, size_t, int, const struct sockaddr *,
        socklen_t);
int     setsockopt(int, int, int, const void *, socklen_t);
int     shutdown(int, int);
int     sockatmark(int);
int     socket(int, int, int);
int     socketpair(int, int, int, int [2]);

相关网站
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_socket.h.html
http://www.ing.iac.es/~docs/external/susv3/basedefs/sys/socket.h.html