Client abnormally terminates when server isn't found

Hi there,

I just made a server and client programs (finally!!) but there's a problem with my client program. The problem is , when the server isn't up , the client abnormally terminates and displays a windows error (the one with "send report" ..etc). How do i check if the server is up , and if not , try another address for example?

here's my client's simple code :

Code:

---

#include <stdio.h>
#include <winsock.h>
#include <stdlib.h>
#include <windows.h>
#include <string.h>


int main(void)
{
        WSAData wsadata;
        WORD ver;
        char buffer[256];
       

        ver = MAKEWORD(1,1);

        WSAStartup(ver, &wsadata);

        LPHOSTENT hostEntry;

        hostEntry = gethostbyname("localhost");

        if(!hostEntry)
        {
                printf("Error getting host : %s\n", WSAGetLastError());
                WSACleanup();
                return 1;
        }

        printf("Host gathered ..\n");

        SOCKET theSocket;

        theSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

        if(theSocket == INVALID_SOCKET)
        {
                printf("Error socket : %s\n", WSAGetLastError());
                system("PAUSE");
                WSACleanup();
                return 1;
        }

        printf("Socket created ..\n");

        SOCKADDR_IN serverInfo;

        serverInfo.sin_family = AF_INET;
        serverInfo.sin_addr = *((LPIN_ADDR)*hostEntry->h_addr_list);
        serverInfo.sin_port = htons(666);


        if(connect(theSocket, (LPSOCKADDR)&serverInfo,
                sizeof(sockaddr)) == -1)
        {
                printf("Error connectiog : %s", WSAGetLastError());
                WSACleanup();
                return 1;
        }

        printf("connected ... \n\n\n");



        printf("> ");

        fgets(buffer, sizeof(buffer), stdin);


        if( send(theSocket, buffer, strlen(buffer), 0) == SOCKET_ERROR)
        {
                printf("Error getting host : %s", WSAGetLastError());
                WSACleanup();
                return 1;
        }


        closesocket(theSocket);
        WSACleanup();

        return 0;
}

---

Edit : i forgot to mention that the program reaches "connect()" before it termiates , and it won't display an error even though i used error checking.

help is much appreciated..

Code:

---

        printf("Error connectiog : %s", WSAGetLastError());

---

WSAGetLastError does not return a string.

GAH!! stupid me *smacks forehead on table*. Turns out my error checking needs error checking .. hehe :p

btw , whats a good resource to learn about Asynchronous sockets? (except for Johnnie's tutorial)

This one was decent. Although I think there were a few minor errors in there if I remember correctly..

looks good JaWiB , thanks :)

From the tutorial :

Quote:

---

Non-blocking sockets can be used in console apps, asynchronous sockets cannot.

---

*gasps* WHAT???? :confused:

how come i can't use asynchronous sockets in console apps? does this force me to learn Windows programming , or is there another way around it??

Only WSAAsyncSelect requires the windows program stuff (i.e. a window procedure and message pump). Other async. methods don't.

I can only find tutorials using WSAAsyncSelect() function. Where can i find tutorials teaching the "other" methods for windows?

MSDN basically explains how to use them..

how about you name those functions so i can research them ? :)

Sorry -

WSAEventSelect
GetQueuedCompletionStatus with CreateIOCompletionPort
Standard blocking sockets in multiple threads is async too, because threads are async by definition.