在 C 中创建套接字时取消引用空指针

Question

I'm trying to convert a program developed in linux to visual studio. The program is in C language. I tried replacing the socket functions from socket.h to the ones from visual studio. This is what I have so far.

#define _CRT_SECURE_NO_WARNINGS
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x6000
#endif
#undef UNICODE
#define UNICODE
#undef _WINSOCKAPI_
#define _WINSOCKAPI_

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

#define _CRT_SECURE_NO_WARNINGS

struct the_socks
{
    int sock_file_d;
    struct sockaddr_in my_addr;
};

int  main()
{
    struct the_socks* my_sock;
    int state = -1;

    my_sock = (struct the_socks*)malloc(sizeof(struct the_socks));

    struct sockaddr_in client_n, server_n;

    if ((my_sock->sock_file_d = socket(AF_INET, SOCK_STREAM, 0)) >= 0)
    {
        state = 0;
    }
}

I didn't get an error in linux even though the code is very similar. I'm getting the following error when I build:

Severity    Code    Description Project File    Line    Suppression State   Detail Description
Warning C6011   Dereferencing NULL pointer 'my_sock'.   Project3    C:\Users\stuff\source\main.c    33  

I would appreciate any suggestions thanks.

Answer 1

I added an init function for winsock. Looks like that was the problem because it built fine now. Can someone verify? Thanks.

#define _CRT_SECURE_NO_WARNINGS
#ifndef _WIN32_WINNT
#define _WIN32_WINNT 0x6000
#endif
#undef UNICODE
#define UNICODE
#undef _WINSOCKAPI_
#define _WINSOCKAPI_

#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#include <stdlib.h>
#include <stdio.h>

#define _CRT_SECURE_NO_WARNINGS

#pragma comment(lib,"ws2_32.lib") //Winsock Library

struct the_socks
{
    int sock_file_d;
    struct sockaddr_in my_addr;
};

int  main()
{
    WSADATA wsa;

    printf("\nInitialising Winsock...");
    if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0)
    {
        printf("Failed. Error Code : %d", WSAGetLastError());
        return 1;
    }

    printf("Initialised.");


    struct the_socks* my_sock;
    int state = -1;

    my_sock = (struct the_socks*)malloc(sizeof(struct the_socks));

    struct sockaddr_in client_n, server_n;

    if ((my_sock->sock_file_d = socket(AF_INET, SOCK_STREAM, 0)) >= 0)
    {
        state = 0;
    }
    //do other stuff
    return 0;
}