在过去的5个小时里，我已经倾倒了我的代码而且无处可去。每当我运行我的代码时，我都会遇到分段错误。有时它发生在客户端，有时在服务器端，所以我只是不确定发生了什么。 当我尝试查找高达100的素数时，代码有效，但之后没有。当我上次发布此消息时，我被告知要发布完整的代码，所以这里是：
服务器
void sieve(int *isComposite, int maximum, int maxSqrt) {
int m = isComposite[0];
int currentPrime = m-1;
//Loop through "maxSqrt" times through the array
if(m <= maxSqrt){
//Loop through the multiples of the number we're
//looking at (m) and mark them as composite (1)
for (int k = currentPrime * currentPrime; k <= maximum; k += currentPrime){
if(isComposite[k+1] == 0){
//cout << "Removing: " << k << endl;
isComposite[k+1] = 1;
}
}
}
}
int main(int argc, char *argv[]){
int sockfd, newsockfd, portno; // listen on sock_fd, new connection on new_fd, port number
socklen_t clilen;
struct sockaddr_in serv_addr, cli_addr; // my address information, connector's address information
int n;
int open = 1; //true
if (argc < 2) {
fprintf(stderr,"ERROR, no port provided\n");
exit(1);
}
//Socket setup
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
error("ERROR opening socket");
}
bzero((char *) &serv_addr, sizeof(serv_addr));
portno = atoi(argv[1]); //port number (ex. 10.12.110.57 or thing-1.uwec.edu)
serv_addr.sin_family = AF_INET; // host byte order
serv_addr.sin_port = htons(portno); // short, network byte order
serv_addr.sin_addr.s_addr = INADDR_ANY; // use my IP address
//Bind socket
if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
error("ERROR on binding");
}
//Listen for connection
listen(sockfd,5);
//Accept the connection
clilen = sizeof(cli_addr);
newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);
if (newsockfd < 0){
error("ERROR on accept");
}
printf("Connection accepted!\n");
// Variable to college the largest number in the range
int maximum;
// Collect the maximum
cout << "\nEnter a Maximum:";
cin >> maximum;
cout << "\n";
int *maxToSend = new int[1];
maxToSend[0] = maximum;
if(send(newsockfd, maxToSend, 10, 0) < 0){
perror("ERROR sending to socket");
}
int maxSqrt = (int)sqrt((double)maximum);
// Declare the array to hold important
// information and the numbers to sieve
int *isComposite= new int[maximum+1]();
// Insert the variable that keeps track of where we
// are in the array, starting with 2 (the first prime)
// which is held in isComposite[3]
isComposite[0] = 3;
// Run the sieve for each prime we come accross
// until we reach the prime that is the square
// root of the maximum (isComposite[2])
while(isComposite[0] <= maxSqrt){
// Unless it is the first time through
// Receive from the client
if(isComposite[0] > 3){
if(recv(newsockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
perror("ERROR receiving from socket");
}
}
// If we're not done:
if(isComposite[0] <= maxSqrt){
// Sieve the range
sieve(isComposite, maximum, maxSqrt);
isComposite[0]++;
// Find the next prime
while(isComposite[isComposite[0]] == 1){
isComposite[0]++;
}
cout << "Doing next Sieve on: " << isComposite[0]-1 << endl;
}
// If we're still not done:
if(send(newsockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
if(send(newsockfd, isComposite, maximum+1500, 0) < 0){
perror("ERROR sending to socket");
}
}
}
return 0;
}
客户端：
void sieve(int *isComposite, int maximum, int maxSqrt) {
int m = isComposite[0];
int currentPrime = m-1;
//Loop through "maxSqrt" times through the array
if(m <= maxSqrt){
//Loop through the multiples of the number we're
//looking at (m) and mark them as composite (1)
for (int k = currentPrime * currentPrime; k <= maximum; k += currentPrime){
if(isComposite[k+1] == 0){
//cout << "Removing: " << k << endl;
isComposite[k+1] = 1;
}
}
}
}
int main(int argc, char *argv[]){
int sockfd, portno, n;
struct sockaddr_in serv_addr;
struct hostent *server;
int open = 1; //true
char c = 'a';
if (argc < 3) {
fprintf(stderr,"usage %s hostname port\n", argv[0]);
exit(0);
}
portno = atoi(argv[2]); //parse port number
sockfd = socket(AF_INET, SOCK_STREAM, 0);
if (sockfd < 0) {
error("ERROR opening socket");
}
server = gethostbyname(argv[1]);
if (server == NULL) {
fprintf(stderr,"ERROR, no such host\n");
exit(0);
}
bzero((char *) &serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET; // host byte order
bcopy((char *)server->h_addr,(char *)&serv_addr.sin_addr.s_addr, server->h_length);
serv_addr.sin_port = htons(portno); // short, network byte order
if (connect(sockfd,(struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0) {
error("ERROR connecting");
}
int *maxToSend = new int[1];
if(recv(sockfd, maxToSend, 10, 0) < 0){
perror("ERROR receiving from socket");
}
int maximum = maxToSend[0];
int maxSqrt = (int)sqrt((double)maximum);
int *isComposite= new int[maximum+1]();
while(isComposite[0] <= maxSqrt){
if(recv(sockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
perror("ERROR receiving from socket");
}
// Sieve the range
sieve(isComposite, maximum, maxSqrt);
isComposite[0]++;
// Find the next prime
while(isComposite[isComposite[0]] == 1){
isComposite[0]++;
}
cout << "Doing next Sieve on: " << isComposite[0]-1 << endl;
if(send(sockfd, isComposite, (maximum+1)* sizeof(int), 0) < 0){
perror("ERROR sending to socket");
}
}
close(sockfd);
return(0);
}
答案 0 :(得分：3)
原因是筛子的大小比单个包装容量大。您只能在一个数据包中存储大约1400个字节，并且您的发送和接收功能不会考虑这一点。您必须循环，直到您发送了您尝试发送的所有数据或读取您尝试读取的所有数据。您似乎尝试使用send(newsockfd, isComposite, maximum+1500, 0)执行此操作，但是您需要使用循环执行此操作，并跟踪从send的返回值发送的数据量。
一个简单的函数可能看起来像
bool sendAll(int socket, const void *data, ssize_t size) {
ssize_t sent = 0;
ssize_t just_sent;
while (sent < size) {
just_sent = send(socket, data + sent, size - sent, 0);
if (just_set < 0) {
return false;
}
sent += just_sent;
}
return true;
}
recv的类似内容。