Date: Thu, 29 Apr 1999 12:38:16 -0400 (EDT) From: Naief BinTalal <naief@cyfari.com> To: Greg Campbell <greg.campbell@matrikon.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: socket communication Message-ID: <Pine.BSF.4.05.9904291226190.90679-100000@destroyer.cyfari.com> In-Reply-To: <000f01be9323$ce6e5bf0$9308a8c0@matrikon.com>
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On Fri, 30 Apr 1999, Greg Campbell wrote:
> Hi,
>
> I would appreciate some words of wisdom from anyone
> who has done some socket programming on FreeBSD.
>
> The question is this:
> Is there anything special about connecting to a
> socket from FreeBSD? I am getting an error from
> the "connect" function call (nothing more than
> -1 is returned which doesn't seem to map to any
> error messages codes.
>
> The following code is what I reverted to. It is
> basically the example form the Horspool book:
>
> #include <stdio.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <netinet/in.h>
> #include <netdb.h>
>
> #define HOSTNAME "pandora"
> #define PORTNUM 2000
> #define oops(msg) {printf("%s\n",msg);exit(-1);}
>
> struct sockaddr_in bba;
> struct hostent *hp;
> FILE *rf;
> int s, rfd, ch;
>
>
> int main()
> {
> int x;
> char return_char;
> int retval;
>
> /* build the network address */
> bzero(&bba, sizeof(bba));
> bba.sin_family = AF_INET;
> hp=gethostbyname(HOSTNAME);
> if(hp==NULL) oops ("no such computer");
> bcopy(hp->h_addr, &bba.sin_addr, hp->h_length);
> bba.sin_port = htons(PORTNUM);
>
> /* make the connection */
> s = socket(AF_INET, SOCK_STREAM, 0);
> if(s==-1) oops("socket");
> if((retval=connect(s,&bba, sizeof(bba)))!= 0)
cast bba to the generic socket address ie:
if((retval=connect(s,(struct sockaddr *)&bba,sizeof(bba))) ..
> oops("connect");
the connect system call will return -1 on error and set errno to the
interger that maps to the error. If you want to know what happed you can
display the error using strerror ie:
#include <string.h>
extern errno;
#define sysoops(msg) {printf("%s: %s\n",msg,strerro(errno));exit(-1);}
sysoops("connect error");
>
> rf=fdopen(s,"r");
> }
>
>
> The connect call in this snippet always returns
> -1 and the program drops out with the "connect"
> message.
>
> Let me say that the socket is open on another
> FreeBSD box. A HP-UX workstation and a Windows PC
> can both connect to the socket. The HP-UX box is
> using this same code as the connection client
> (although that really doesn't mean much - other
> than I have quite a bit of computer crap in my
> basement and extra time on my hands).
>
> Is there anything that has to be turned on in the
> kernal to support sockets? I am grasping at straws
> here.
>
> Any help would be appreciated.
>
> thanks,
> Greg
>
Hope this helps ...
Naief
---------------------------------------------------------------------
Naief BinTalal Senior Engineer naief@cyfari.com
CyFari Inc The Commerce Engine
Network Operations Center. http://www.cyfari.com
Daytona Beach Florida. Tel: 904-258-1116
USA. Fax: 904-257-1311
>
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