Libcurl获取缓冲区中的标题内容
我尝试使用libcurl获取网页的标题内容,并尝试将其存储在charecter缓冲区中。该程序给出了分段错误。我是libcurl的初学者,不确定问题出在哪里。下面是代码Libcurl获取缓冲区中的标题内容,c,libcurl,C,Libcurl,我尝试使用libcurl获取网页的标题内容,并尝试将其存储在charecter缓冲区中。该程序给出了分段错误。我是libcurl的初学者,不确定问题出在哪里。下面是代码 #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <assert.h> #include <curl/curl.h> str
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#include <curl/curl.h>
struct buf {
char *buffer;
size_t bufferlen;
size_t writepos;
} buffer = {0};
struct buf HeaderBuffer;
static size_t write_data(void *ptr, size_t size, size_t nmemb, char *string)
{
size_t nbytes = size*nmemb;
if (!HeaderBuffer.buffer) {
HeaderBuffer.buffer = malloc(1024);
HeaderBuffer.bufferlen = 1024;
HeaderBuffer.writepos = 0;
}
if (HeaderBuffer.writepos + nbytes < HeaderBuffer.bufferlen) {
HeaderBuffer.bufferlen = 2 * HeaderBuffer.bufferlen;
HeaderBuffer.buffer = (char *)realloc(HeaderBuffer.buffer, buffer.bufferlen);
}
assert(HeaderBuffer.buffer != NULL);
memcpy(HeaderBuffer.buffer+HeaderBuffer.writepos,ptr,nbytes);
return nbytes;
}
int main(void)
{
CURL *curl_handle;
curl_global_init(CURL_GLOBAL_ALL);
/* init the curl session */
curl_handle = curl_easy_init();
curl_easy_setopt(curl_handle, CURLOPT_URL, "http://example.com");
/* send all data to this function */
curl_easy_setopt(curl_handle,CURLOPT_HEADERFUNCTION, write_data);
/* get it! */
curl_easy_perform(curl_handle);
printf("%s",HeaderBuffer.buffer);
/* cleanup curl stuff */
curl_easy_cleanup(curl_handle);
return 0;
}
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结构单元{
字符*缓冲区;
大小缓冲区;
写入的大小;
}缓冲区={0};
结构buf HeaderBuffer;
静态大小写入数据(void*ptr、size\t size、size\t nmemb、char*string)
{
大小字节=大小*nmemb;
如果(!HeaderBuffer.buffer){
HeaderBuffer.buffer=malloc(1024);
HeaderBuffer.bufferlen=1024;
HeaderBuffer.writepos=0;
}
if(HeaderBuffer.writepos+n字节
编辑:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>
struct string {
char *ptr;
size_t len;
};
void init_string(struct string *s) {
s->len = 0;
s->ptr = (char *)malloc(s->len+1);
if (s->ptr == NULL) {
fprintf(stderr, "malloc() failed\n");
exit(1);
}
s->ptr[0] = '\0';
}
size_t writefunc(void *ptr, size_t size, size_t nmemb, struct string *s)
{
size_t new_len = s->len + size*nmemb;
s->ptr =(char *) realloc(s->ptr, new_len+1);
if (s->ptr == NULL) {
fprintf(stderr, "realloc() failed\n");
exit(EXIT_FAILURE);
}
memcpy(s->ptr+s->len, ptr, size*nmemb);
//sprintf (s->ptr+s->len,"New header:\n%s\n",(char *)ptr);
s->ptr[new_len] = '\0';
s->len = new_len;
return size*nmemb;
}
int main(void)
{
CURL *curl;
CURLcode res;
char url[50];
char *ptr=NULL;
int i=0;
memset(Buffer,0,255);
strcpy(url,"http://");
strncat(url,"74.125.236.176",strlen("74.125.236.176"));
curl = curl_easy_init();
if(curl) {
struct string s;
init_string(&s);
curl_easy_setopt(curl, CURLOPT_URL,url);
curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, writefunc);
curl_easy_setopt(curl, CURLOPT_WRITEHEADER, &s);
res = curl_easy_perform(curl);
printf("\n \n %s",Buffer);
printf("%s\n", s.ptr);
free(s.ptr);
/* always cleanup */
curl_easy_cleanup(curl);
}
return 0;
}
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结构字符串{
char*ptr;
尺寸透镜;
};
void init_字符串(结构字符串*s){
s->len=0;
s->ptr=(char*)malloc(s->len+1);
如果(s->ptr==NULL){
fprintf(stderr,“malloc()失败\n”);
出口(1);
}
s->ptr[0]='\0';
}
大小写函数(void*ptr、大小、大小nmemb、结构字符串*s)
{
大小\u t新长度=s->len+size*nmemb;
s->ptr=(char*)realloc(s->ptr,new_len+1);
如果(s->ptr==NULL){
fprintf(stderr,“realloc()失败\n”);
退出(退出失败);
}
memcpy(s->ptr+s->len,ptr,size*nmemb);
//sprintf(s->ptr+s->len,“新标题:\n%s\n”,(char*)ptr);
s->ptr[new_len]='\0';
s->len=新镜头;
返回大小*nmemb;
}
内部主(空)
{
卷曲*卷曲;
卷曲编码;
字符url[50];
char*ptr=NULL;
int i=0;
memset(缓冲区,0255);
strcpy(url,“http:/”);
strncat(url,“74.125.236.176”,strlen(“74.125.236.176”);
curl=curl_easy_init();
if(curl){
结构字符串s;
初始化字符串(&s);
curl_easy_setopt(curl,CURLOPT_URL,URL);
curl\u easy\u setopt(curl,CURLOPT\u HEADERFUNCTION,writefunc);
curl\u easy\u setopt(curl、CURLOPT\u WRITEHEADER和s);
res=旋度(curl)\u容易执行(curl);
printf(“\n\n%s”,缓冲区);
printf(“%s\n”,s.ptr);
免费(s.ptr);
/*总是清理*/
旋度\轻松\清洁(旋度);
}
返回0;
}
在这里,我想你应该这样做
HeaderBuffer.bufferlen=nbytes*HeaderBuffer.bufferlen代码>
由于您不知道N字节,它可能大于2*HeaderBuffer.bufferlen
在调试器中运行它。所以不是调试服务。当您遇到诸如分段错误之类的崩溃时,您应该在调试器中运行该程序。调试器将在崩溃时停止,并允许您检查(甚至遍历)函数调用堆栈。如果它在一个系统函数中停止,那么沿着堆栈一直走到您的代码,然后您就可以检查变量的值了。@n.m.@joachim Pileborg:问题现在已经解决了