cannot send nor receive data through sockets - c++

Question

I tried making a simple server-client socket communication but something seems to no work properly with the server. I get this error whenever I send or receive:
Socket operation on non-socket: Socket operation on non-socket
Strangely enough, this only appears whenever the server is sending.
the client seems to be ok:
//server
#include <iostream>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <arpa/inet.h>
using namespace std;
int main(){
const int PORT = 5000;
int serverfd, clientfd, opt=1, n_send, n_recv;
sockaddr_in server_address, client_address;
char recvbuf[1024], sendbuf[1024];
bzero(&server_address , sizeof(server_address));
inet_pton(AF_INET, "127.0.0.1",&server_address.sin_addr);
int x = INADDR_ANY;
server_address.sin_family = AF_INET;
server_address.sin_port = htons(PORT);
socklen_t addrSize = sizeof(server_address);
if((serverfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
if((setsockopt(serverfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) < 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
if((bind(serverfd, (sockaddr*)&server_address, sizeof(server_address)))< 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
if((listen(serverfd, 1))< 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
if((clientfd = accept(serverfd, (sockaddr *)&server_address, (socklen_t*)&addrSize) < 0)){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
while (true){
cout << "SAY TO CLIENT: ";
bzero(sendbuf, sizeof(sendbuf));
cin >> sendbuf;
cout << endl;
send(clientfd, sendbuf, strlen(sendbuf), 0);
errno = 0;
bzero(recvbuf, sizeof(recvbuf));
if((n_recv = recv(clientfd, recvbuf, sizeof(recvbuf), MSG_WAITALL))< 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
cout << recvbuf << endl;
}
return 0;
}
//client
#include <iostream>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <arpa/inet.h>
using namespace std;
int main(){
const int PORT = 5000;
int sockfd, n_send, n_recv;
char recvbuf[1024], sendbuf[1024];
sockaddr_in server_address;
bzero(&server_address, sizeof(server_address));
server_address.sin_family= AF_INET;
server_address.sin_port = htons(PORT);
inet_pton(AF_INET, "127.0.0.1", &server_address.sin_addr);
if((sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
if(connect(sockfd, (sockaddr *) &server_address, sizeof(server_address))<0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
while (true){
if((n_recv = recv(sockfd, recvbuf, sizeof(recvbuf), MSG_WAITALL)) < 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
cout << "Server: " << recvbuf << endl;
cout << "Say to server: ";
cin >> sendbuf;
cout << endl;
if((n_send = send(sockfd, sendbuf, sizeof(sendbuf), 0)) < 0){
perror(strerror(errno));
exit(EXIT_FAILURE);
}
}
return 0;
}

Answer 1

clientfd is assigned a non-socket value. If we change the whitespace in your if:
if((clientfd =
accept(serverfd, (sockaddr *)&server_address, (socklen_t*)&addrSize) < 0
)) {
perror(strerror(errno));
exit(EXIT_FAILURE);
}
Because of the way you wrote it, the result of accept (the presumably valid socket) is checked, and that result is set to clientFd. Note that your parenthesis placement doesn't match your other lines.