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@hex128
Last active July 30, 2016 17:27
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Example C TCP socket client
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>
int main(int argc, char *argv[]) {
int sockfd;
ssize_t n;
uint16_t portno;
struct sockaddr_in serv_addr;
struct hostent *server;
char buffer[256];
if (argc < 3) {
fprintf(stderr, "Usage: %s <host> <port>\n", argv[0]);
exit(1);
}
portno = (uint16_t) atoi(argv[2]);
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
perror("Error opening socket\n");
exit(2);
}
server = gethostbyname(argv[1]);
if (server == NULL) {
fprintf(stderr, "Host not found\n");
exit(3);
}
bzero(&serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
bcopy(server->h_addr, (char *) &serv_addr.sin_addr.s_addr, (size_t) server->h_length);
serv_addr.sin_port = htons(portno);
if (connect(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
perror("ERROR connecting\n");
exit(4);
}
printf("Please enter the message: ");
bzero(buffer, 256);
fgets(buffer, 255, stdin);
n = write(sockfd, buffer, strlen(buffer));
if (n < 0) {
perror("ERROR writing to socket\n");
exit(5);
}
bzero(buffer, 256);
n = read(sockfd, buffer, 255);
if (n < 0) {
perror("Error reading from socket\n");
exit(6);
}
printf("%s\n", buffer);
return 0;
}
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