Re: newbie: socket api

From:

Thomas Kaufmann <tokauf@googlemail.com>

Newsgroups:

comp.lang.c++

Date:

Wed, 26 Dec 2012 14:13:20 -0800 (PST)

Message-ID:

<f067934f-c936-48ea-854f-5220718c5d36@googlegroups.com>

Am Mittwoch, 26. Dezember 2012 23:02:08 UTC+1 schrieb Ian Collins:

Thomas Kaufmann wrote:

Hi there,

Please wrap your lines!

I use the socket-API. My Problem is:

I have a function (yes, a function not a method). And I want return

either the struct sockaddr_in or sockaddr_in6. How can do this? I

tried a void-pointer but there is an error-message.

What did you try? What error did you get?

--

Ian Collins

Here is my code:

#include "unp.h"
#include "init.h"

#include <exception>

void* InitAndConnect(int sockfd, int family, char *ip) {

  // I want return this struct
  struct sockaddr sa;

  if (family == AF_INET) {

    try {

      struct sockaddr_in servaddr;;

      bzero(&servaddr, sizeof(servaddr) );
      servaddr.sin_family = family;
      servaddr.sin_port = htons(SERV_PORT);

      if (inet_pton(family, ip, &servaddr.sin_addr) <= 0) {
    perror("inet_pton-error: ");
      }

      connect(sockfd, (SA*) &servaddr, sizeof(servaddr) );

      // critical line
      sa = servaddr;

    } catch(std::exception& e) {
      cout << e.what() << endl;
    }

  } else if (family == AF_INET6) {

    struct sockaddr_in6 servaddr;

    bzero(&servaddr, sizeof(servaddr) );
    servaddr.sin6_family = AF_INET;
    servaddr.sin6_port = htons(SERV_PORT);
    inet_pton(family, ip, &servaddr.sin6_addr);

    connect(sockfd, (SA*) &servaddr, sizeof(servaddr) );

      // critical line
      sa = servaddr;
  }

  // does' work
  return sa;
}

int main(int argc, char *argv[]) {

  int sockfd = socket(AF_INET, SOCK_STREAM, 0);
  void* ptr = InitAndConnect(int sockfd, AF_INET, argv[1]) {

  return 0;
}

Here are the errors:

xxx54@richard:~/myC++/unp/derplan> g++ -o init -Wall -pedantic -O3 init_tes=
t.cpp
init_test.cpp: In function =91void* InitAndConnect(int, int, char*)':
init_test.cpp:28:12: error: no match for =91operator=' in =91sa = ser=
vaddr'
/usr/include/bits/socket.h:179:3: note: candidate is: sockaddr& sockaddr::o=
perator=(const sockaddr&)
init_test.cpp:46:12: error: no match for =91operator=' in =91sa = ser=
vaddr'
/usr/include/bits/socket.h:179:3: note: candidate is: sockaddr& sockaddr::o=
perator=(const sockaddr&)
init_test.cpp:50:10: error: cannot convert =91sockaddr' to =91void*' in=
return
init_test.cpp: In function =91int main(int, char**)':
init_test.cpp:56:31: error: expected primary-expression before =91int'
init_test.cpp:56:61: error: expected =91,' or =91;' before =91{' toke=
n
init_test.cpp:55:7: warning: unused variable =91sockfd'
init_test.cpp:56:9: warning: unused variable =91ptr'
init_test.cpp:59:1: error: expected =91}' at end of input
init_test.cpp: In function =91void* InitAndConnect(int, int, char*)':
init_test.cpp:51:1: warning: control reaches end of non-void function
xxx54@richard:~/myC++/unp/derplan>