【本文谢绝转载,原文来自http://990487026.blog.51cto.com】

chunli魂斗罗~$ cat main.c
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <curl/curl.h>
#include <string.h>
#include <ctype.h>
#include <iconv.h>
#define TMP_FILE "tmp.html"
#define HTML_BUFFER_SIZE 1024*800  void split(char **arr, char *str, const char *del) {  char *s = strtok(str, del);  while (s != NULL) {  *arr++ = s;  s = strtok(NULL, del);  }
}  /*将str1字符串中第一次出现的str2字符串替换成str3*/
void replaceFirst(char *str1, char *str2, char *str3) {  char str4[strlen(str1) + 1];  char *p;  strcpy(str4, str1);  if ((p = strstr(str1, str2)) != NULL)/*p指向str2在str1中第一次出现的位置*/ {  while (str1 != p && str1 != NULL)/*将str1指针移动到p的位置*/ {  str1++;  }  str1[0] = '\0'; /*将str1指针指向的值变成/0,以此来截断str1,舍弃str2及以后的内容，只保留str2以前的内容*/  strcat(str1, str3); /*在str1后拼接上str3,组成新str1*/  strcat(str1, strstr(str4, str2) + strlen(str2)); /*strstr(str4,str2)是指向str2及以后的内容(包括str2),strstr(str4,str2)+strlen(str2)就是将指针向前移动strlen(str2)位，跳过str2*/  }
}  /*将str1出现的所有的str2都替换为str3*/
void replace(char *str1, char *str2, char *str3) {  while (strstr(str1, str2) != NULL) {  replaceFirst(str1, str2, str3);  }
}  /*截取src字符串中,从下标为start开始到end-1(end前面)的字符串保存在dest中(下标从0开始)*/
void substring(char *dest, char *src, int start, int end) {  int i = start;  if (start > strlen(src))return;  if (end > strlen(src))  end = strlen(src);  while (i < end) {  dest[i - start] = src[i];  i++;  }  dest[i - start] = '\0';  return;
}  /*返回src中下标为index的字符*/
char charAt(char *src, int index) {  char *p = src;  int i = 0;  if (index < 0 || index > strlen(src))  return 0;  while (i < index)i++;  return p[i];
}  /*返回str2第一次出现在str1中的位置(下表索引),不存在返回-1*/
int indexOf(char *str1, char *str2) {  char *p = str1;  int i = 0;  p = strstr(str1, str2);  if (p == NULL)  return -1;  else {  while (str1 != p) {  str1++;  i++;  }  }  return i;
}  /*返回str1中最后一次出现str2的位置(下标),不存在返回-1*/
int lastIndexOf(char *str1, char *str2) {  char *p = str1;  int i = 0, len = strlen(str2);  p = strstr(str1, str2);  if (p == NULL)return -1;  while (p != NULL) {  for (; str1 != p; str1++)i++;  p = p + len;  p = strstr(p, str2);  }  return i;
}  /*删除str左边第一个非空白字符前面的空白字符(空格符和横向制表符)*/
void ltrim(char *str) {  int i = 0, j, len = strlen(str);  while (str[i] != '\0') {  if (str[i] != 32 && str[i] != 9)break; /*32:空格,9:横向制表符*/  i++;  }  if (i != 0)  for (j = 0; j <= len - i; j++) {  str[j] = str[j + i]; /*将后面的字符顺势前移,补充删掉的空白位置*/  }
}  /*删除str最后一个非空白字符后面的所有空白字符(空格符和横向制表符)*/
void rtrim(char *str) {  char *p = str;  int i = strlen(str) - 1;  while (i >= 0) {  if (p[i] != 32 && p[i] != 9)break;  i--;  }  str[++i] = '\0';
}  /*删除str两端的空白字符*/
void trim(char *str) {  ltrim(str);  rtrim(str);
}  //这是libcurl接收数据的回调函数，相当于recv的死循环
//其中stream可以自定义数据类型，这里我传入的是文件保存路径  static size_t write_callback(void *ptr, size_t size, size_t nmemb, void *stream) {  int len = size * nmemb;  int written = len;  FILE *fp = NULL;  const char *pathfile = (const char*)stream;if (access(pathfile,0) == -1) {  fp = fopen((char*) stream, "wb");  } else {  fp = fopen((char*) stream, "ab");  }  if (fp) {  fwrite(ptr, size, nmemb, fp);  }  // printf("%s\n",ptr);  fclose(fp);  return written;
}
//加上-lcurl库  void test_post(char* url,char* data) {  CURL *curl;  curl = curl_easy_init();  if (curl) {  //www.baidu.com/#wd=java  curl_easy_setopt(curl, CURLOPT_URL, url);  curl_easy_setopt(curl, CURLOPT_POST, 1L);  curl_easy_setopt(curl, CURLOPT_POSTFIELDS, data);  curl_easy_perform(curl);  curl_easy_cleanup(curl);  }  fclose(curl);
}  int file_exists(char *filename) {  return (access(filename, 0) == 0);
}
int GetCharset(char *src_html,char *charCode) {  char tmp_html[HTML_BUFFER_SIZE]={0};  int pos = indexOf(src_html, "text/html; charset=");  if (pos > 0) {  strncpy(tmp_html, src_html + pos + strlen("text/html; charset="), strlen(src_html) - pos);  pos = indexOf(tmp_html, "\"");  if (pos > 0) {  strncpy(charCode, tmp_html, pos);  }  }  return 0;  }  void test_get(char* url) {  CURL *curl;  CURLcode res;  curl = curl_easy_init();  if (curl) {  if (file_exists(TMP_FILE))  remove(TMP_FILE);  curl_easy_setopt(curl, CURLOPT_URL, url);  //指定回调函数  curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_callback);  //这个变量可作为接收或传递数据的作用  curl_easy_setopt(curl, CURLOPT_WRITEDATA, TMP_FILE);  res = curl_easy_perform(curl);  char tocode[64] = "UTF-8";  if (CURLE_OK == res) {  char *ct;  res = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &ct);  if ((CURLE_OK == res) && ct)  printf("We received Content-Type: %s\n", ct);  //printf("====\n");  //int pos=strcspn(ct,"UTF-8");   int index = indexOf(ct, "=");  char* arr[3];  if (index > 0) {  split(arr, ct, "=");  //printf("%s\n", arr[1]);  strcpy(tocode, arr[1]);  }  FILE *fp = NULL;  fp = fopen(TMP_FILE, "r");  char src_html[HTML_BUFFER_SIZE]={0};  char *src_html_p = src_html;size_t srclen = strlen(src_html);char output_html[HTML_BUFFER_SIZE]={0};  char *output_html_p = output_html;size_t  outlen = 0;  char tmp_html[HTML_BUFFER_SIZE]={0};  if (fp) {  fread(src_html, HTML_BUFFER_SIZE, 1, fp);     strcpy(tmp_html,src_html);  if(index <0) {  GetCharset(tmp_html,tocode);  printf("%s\n",tocode);  }  //打开字符集转换    iconv_t hIconv = iconv_open(tocode,"iso-8859-1");  if (-1 == (ssize_t)hIconv) {  return ; //打开失败，可能不支持的字符集    }       printf("%s\n",src_html);  //开始转换    //size_t iconv(iconv_t cd,char **inbuf, size_t *inbytesleft,char **outbuf, size_t *outbytesleft);size_t ret = iconv(hIconv,&src_html_p,&srclen,&output_html_p,&outlen);                  if(ret == -1){printf("转换失败\n");exit(2);}//printf("%s\n", output_html);    //printf("ok");  if(strcmp(output_html,"")==0)  {  printf("%s\n",src_html);  }  //关闭字符集转换    iconv_close(hIconv);  }  }  curl_easy_cleanup(curl);  }
}  int main(int argc, char** argv) {  //test_post("https://www.baidu.com/","");  test_get("http://www.baidu.com/");  return 0;
}
chunli魂斗罗~$

编译运行:

chunli魂斗罗~$ gcc main.c -Wall  -l curl && ./a.out
We received Content-Type: text/html
UTF-8
<!DOCTYPE html><!--STATUS OK-->
<html>
<head><meta http-equiv="content-type" content="text/html;charset=utf-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><link rel="dns-prefetch" href="//s1.bdstatic.com"/><link rel="dns-prefetch" href="//t1.baidu.com"/><link rel="dns-prefetch" href="//t2.baidu.com"/><link rel="dns-prefetch" href="//t3.baidu.com"/><link rel="dns-prefetch" href="//t10.baidu.com"/><link rel="dns-prefetch" href="//t11.baidu.com"/><link rel="dns-prefetch" href="//t12.baidu.com"/><link rel="dns-prefetch" href="//b1.bdstatic.com"/><title>百度一下，你就知道</title><link href="http://s1.bdstatic.com/r/www/cache/static/home/css/index.css" rel="stylesheet" type="text/css" /><!--[if lte IE 8]><style index="index" >#content{height:480px\9}#m{top:260px\9}</style><![endif]--><!--[if IE 8]><style index="index" >#u1 a.mnav,#u1 a.mnav:visited{font-family:simsun}</style><![endif]--><script>var hashMatch = document.location.href.match(/#+(.*wd=[^&].+)/);if (hashMatch && hashMatch[0] && hashMatch[1]) {document.location.replace("http://"+location.host+"/s?"+hashMatch[1]);}var ns_c = function(){};</script><script>function h(obj){obj.style.behavior='url(#default#homepage)';var a = obj.setHomePage('//www.baidu.com/');}</script><noscript><meta http-equiv="refresh" content="0; url=/baidu.html?from=noscript"/></noscript>   

【本文谢绝转载,原文来自http://990487026.blog.51cto.com】