This code ruined all my day. Basically I have a list of 50 webservers I administrate, I want to check them if up/alive (isAlive() function), I parse my webservers.txt file with the 50 ips/hostnames and for fastness I try to use threads (10, 20 or 30 doesn't matter) then my compiled code seems only duplicate threads with the last line in my file.

Code:
#include <windows.h>
#include <stdio.h>
#include <string.h>
#include <winsock.h>
#include <process.h>
#include <string.h>

#pragma comment(lib, "wsock32.lib")

unsigned int _stdcall isAlive(void *ptr)
{
  struct sockaddr_in blah;
  struct hostent *he;
  WSADATA wsaData;
  int i;
  WORD wVersionRequested;
  SOCKET sock;
  char* addr = (char*)ptr;

  char buff[1024];
  char *ex;
  ex="GET /alive.php HTTP/1.0\n\n";
  char *fmsg="ALIVE";

  wVersionRequested = MAKEWORD(1, 1);
  if (WSAStartup(wVersionRequested , &wsaData)){
    printf("Winsock Initialization failed.\n");
    return(1);
  }

  if ((sock=socket(AF_INET,SOCK_STREAM,0))==INVALID_SOCKET){
    printf("Can not create socket.\n");
    return(1);
  }
  sock = socket(AF_INET,SOCK_STREAM,0);
  blah.sin_family = AF_INET;
  blah.sin_port = htons(80);
  blah.sin_addr.s_addr = inet_addr(addr);

  if ((he=gethostbyname(addr))!=NULL){
    memcpy((char *)&blah.sin_addr.s_addr,he->h_addr,he->h_length);
  }
  else{
    if((blah.sin_addr.s_addr=inet_addr(addr))==-1){
      WSACleanup();
      return(1);
    }
  }

  if (connect(sock,(struct sockaddr*)&blah,sizeof(blah))==0){
    send(sock,ex,strlen(ex),0);
    recv(sock,buff,sizeof(buff),0);
    if(strstr(buff,fmsg)!=NULL){
      printf("ALIVE: %s\n", addr);
    }
  }

  closesocket(sock);
  WSACleanup();
  _endthreadex(0);
  return(1);
}

int main(int argc,char *argv[])
{
  if(argc!=2){
    printf("Usage: %s <webservers list>\n", argv[0]);
    return(1);
  }

  char *inname = argv[1];
  FILE *infile;
  char line_buffer[BUFSIZ];
  char line_number;

  infile = fopen(inname, "r");
  if (!infile) {
    printf("Couldn't open file %s for reading.\n", inname);
    return 0;
  }

  line_number = 0;
  HANDLE hThreadArray[200];
  while (fgets(line_buffer, sizeof(line_buffer), infile)) {
    unsigned threadID;
	hThreadArray[line_number] = (HANDLE)_beginthreadex(0, 0, isAlive, line_buffer, 0, &threadID);
    ++line_number;
  }
  WaitForMultipleObjects(line_number, hThreadArray, TRUE, INFINITE);
  fclose(infile);
  return 0;
}
hosts.txt (11 lines in it)

myhost.com
mysecondhost.com
...
mylasthost.com
result:
C:\Documents and Settings\Xtmtrx\Desktop\Code>checkalive.exe hosts.txt
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com
ALIVE: mylasthost.com