MSVC 10.0 c vs c++ differences

Question

I'm having difficulty compiling the C program below, It's just the begining of me trying to understand winsock. The issue is that when compiling the program client.c, I get an error (C2143) missing ';' before 'type' But when I re-name the source file to 'client.cpp' the program compiles with no errors or warnings. I don't understand the syntax error that is an error in C but not C++.

#define WIN32_LEAN_AND_MEAN
#define DEBUG

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

#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")

#define PORT "12186"
#define BUFFERLEN 512

int main(int argc, char* argv[])
{
    /*
        Variable Declorations
    */
    WSADATA wsaData;
    SOCKET ConnectionSocket = INVALID_SOCKET;
    struct addrinfo *result = NULL, *ptr = NULL, hints;
    int addrResult;

    ZeroMemory(&hints, sizeof(hints));
    hints.ai_family = AF_UNSPEC; //unspecified so we can be compatible with IPv4 and IPv6
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;
    #ifdef DEBUG
    printf("IPPROTO_TCP: %d", IPPROTO_TCP);
    #endif

    //Buffers
    char * sendbuffer; // Error C2143
    char recievebuffer [BUFFERLEN]; //Error C2143

    //Initialize Winsock
    addrResult = WSAStartup(MAKEWORD(2,2), &wsaData);
    if(addrResult !=0)
    {
        printf("WSAStartup failed: %d", addrResult);
    }
    addrResult = getaddrinfo(argv[1], PORT, &hints, &result);
    if(addrResult != 0)
    {
        printf("getaddrinfo failed: %d", addrResult);
        WSACleanup();
        return 1;
    }
    return 0;
}

Edit: C variable declorations have to go before all other code in MSVC C functions. Problem solved. Is this a C89 thing or is it just MSVC?

score 1 · Accepted Answer · answered Jul 12 '12 at 20:27

1

The problem might be the place where variable declarations are going. Place them at the beginning of the function with the other variables.

See the last example from MSDN that can cause this error code.

answered Jul 12 '12 at 20:27

Mahesh

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"In a C program, variables must be declared at the beginning of the function, and they cannot be declared after the function executes non-declaration instructions." Thanks! Moving the variable declarations above the setting values for hints allowed the c compiler to compile with no error. – Parker Philip Roberts-Gibson Jul 12 '12 at 20:40

score 0 · Answer 2 · answered Jul 12 '12 at 20:26

0

The C compiler which ships with VS only implements C89 (seriously...), so you must declare all of your variables at the top of a given function.

answered Jul 12 '12 at 20:26

Ed S.

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MSVC 10.0 c vs c++ differences

2 Answers2