I'm trying to setup a simple TCP client. I don't want the full setup and connect code in my main() so I'm trying to move it to a function but keep getting a Access Violation Error in VS2015, all includes are correct. The function is a straight copy from MSDN.
argc = 2, argv[1] = "localhost", PORT = 27015
Calling function:
win32_connect(&argc, &argv, PORT);
Receiving function:
win32_connect(int *argc, char** argv[], int port)
{
...
iResult = getaddrinfo(argv[1], port, &hints, &result); <- Access Violation
...
}
I just can't figure out a proper way to pass the arguments to the function properly so it works as it does when I have the whole function in main()
Header file (cHeader):
#define _CRT_SECURE_NO_WARNINGS
#ifndef CHEADER_H
#define CHEADER_H
//- Includes
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
//- OS specific includes
#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#pragma comment (lib, "Ws2_32.lib")
#pragma comment (lib, "Mswsock.lib")
#pragma comment (lib, "AdvApi32.lib")
#endif
....
main():
int main(int argc, char *argv[])
{
//- Define variables
int connected = 1;
int sockfd;
char cSend[BUF];
char cRecv[BUF];
//- Create socket + Connect to server
if ((sockfd = win32_connect(argc, argv, PORT)) < 0) {
printf("Failed to connect to server.");
exit(1);
}
...
}
cNetwork.c:
#include "cHeader.h"
#ifdef LINUX
...irrelevant unix code...
#endif
#ifdef _WIN32
int win32_connect(int argc, char* argv[], int port)
{
WSADATA wsaData;
SOCKET ConnectSocket = INVALID_SOCKET;
struct addrinfo *result = NULL,
*ptr = NULL,
hints;
char *sendbuf = "this is a test";
char recvbuf[BUF];
int iResult;
int recvbuflen = BUF;
// Validate the parameters
if (argc != 2) {
//printf("usage: %s server-name\n", argv[0]);
return 1;
}
// Initialize Winsock
iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
if (iResult != 0) {
printf("WSAStartup failed with error: %d\n", iResult);
return 1;
}
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Resolve the server address and port
iResult = getaddrinfo(argv[1], port, &hints, &result);
if (iResult != 0) {
printf("getaddrinfo failed with error: %d\n", iResult);
WSACleanup();
return 1;
}
// Attempt to connect to an address until one succeeds
for (ptr = result; ptr != NULL; ptr = ptr->ai_next) {
// Create a SOCKET for connecting to server
ConnectSocket = socket(ptr->ai_family, ptr->ai_socktype,
ptr->ai_protocol);
if (ConnectSocket == INVALID_SOCKET) {
printf("socket failed with error: %ld\n", WSAGetLastError());
WSACleanup();
return 1;
}
// Connect to server.
iResult = connect(ConnectSocket, ptr->ai_addr, (int)ptr->ai_addrlen);
if (iResult == SOCKET_ERROR) {
closesocket(ConnectSocket);
ConnectSocket = INVALID_SOCKET;
continue;
}
break;
}
freeaddrinfo(result);
if (ConnectSocket == INVALID_SOCKET) {
printf("Unable to connect to server!\n");
WSACleanup();
return 1;
}
return ConnectSocket;
}
#endif
You don't need to pass pointers to argc
and argv
. Just declare the function like this:
int win32_connect(int argc, char *argv[], int port)
And you can use argc
and argv
normally. Then call it like this:
win32_connect(argc, argv, PORT);
EDIT:
You're passing an int
for the second parameter to getaddrinfo
. It expects a const char *
. I don't see a definition for PORT
, but I'm guessing it's a numerical constant.
So if you currently have (for example) this:
#define PORT 1234
Change it to this
#define PORT "1234"
Then define your function like this:
int win32_connect(int argc, char* argv[], const char *port)