简单的传统的阻塞的httpclient

本例来自libevent官网，有一点小小的改动（把google改成了baidu）

#include<netinet/in.h>
#include<sys/socket.h>
#include<netdb.h>
#include<assert.h>
#include<unistd.h>
#include<string.h>
#include<stdio.h>
int main(int argc,char* argv[])
{
	const char query[]=
			"GET / HTTP/1.0\r\n"
			"Host:www.baidu.com\r\n"
			"\r\n";
	const char hostname[]="www.baidu.com";
	struct sockaddr_in sin;
	struct hostent* h;
	const char* cp;
	int fd;
	int n_written,remaining;
	char buf[1024];
	h=gethostbyname(hostname);
	assert(h!=0);
	if(h->h_addrtype!=AF_INET)
	{
		fprintf(stderr,"no ipv6 support,sorry.");
		return 1;
	}
	fd=socket(AF_INET,SOCK_STREAM,0);
	assert(fd>=0);
	sin.sin_family=AF_INET;
	sin.sin_port=htons(80);
	sin.sin_addr=*(struct in_addr*)h->h_addr;
	int ret=connect(fd,(struct sockaddr*)&sin,sizeof(sin));
	assert(ret!=-1);
	cp=query;
	remaining=strlen(query);
	while(remaining)
	{
		n_written=send(fd,cp,remaining,0);
		assert(n_written>0);
		remaining-=n_written;
		cp+=n_written;
	}
	while(1)
	{
		int result=recv(fd,buf,sizeof(buf),0);
		if(result==0)
		{
			break;
		}
		else if(result<0)
		{
			perror("recv");
			close(fd);
			return 1;
		}
		fwrite(buf,1,result,stdout);
	}
	close(fd);
	return 0;
}