字符*功能永不返回值

时间:2016-08-26 07:11:02

标签: c

我是C的新手。这里我编写了一个从浏览器解析http post的函数。这是我的代码:

char* HTTP_POST_GET_BODY(char* HttpPost){

     char* HttpPostBody = strstr(HttpPost,"\r\n\r\n");
     HttpPostBody = HttpPostBody + 4;
     if(strcmp(HttpPostBody,"\r\n\r\n") != 0 && strcmp(HttpPostBody,"") != 0){
         return HttpPostBody;
     }
     else{
        char* HttpPostBody_IE;
        HttpPostBody = strstr(HttpPost,"::");
        char* HttpPostBodyEnd = strstr(HttpPost,"HTTP/1.1");
        int body_length = HttpPostBodyEnd - HttpPostBody;
        strncpy(HttpPostBody_IE,HttpPostBody+2,body_length-2);
        return HttpPostBody_IE;
     }

}

所以基本上,如果程序进入“else”,它应该返回一个指向调用者的char指针。我检查调试器。 HttpPostBody_IE有一个值但是当它返回时它是一个空字符串。

char* http_body = HTTP_POST_GET_BODY(recieve_buffer);

有人对此有所了解吗?

1 个答案:

答案 0 :(得分:2)

您声明指针变量HttpPostBody_IE但从不为它分配内存 对strncpy(....)的调用应该创建一个核心转储。 试试这个:

int body_length = HttpPostBodyEnd - HttpPostBody;
HttpPostBody_IE = (char*)malloc(body_length+1);
strncpy(HttpPostBody_IE,HttpPostBody+2,body_length-2);
return HttpPostBody_IE;

当然,请确保此函数的调用者之后释放已分配的内存 如果函数从if语句中返回,则会出现问题。这是因为在这种情况下没有分配内存。

你可以这样解决它:

static char HttpPostBody_IE[BIG_ENOUGH_FOR_ANY_SOURCE];
if (....)
{
  ...
}
else
{
  ...
  strncpy(HttpPostBody_IE, ...);
  return (HttpPostBody_IE);
}

请注意,这样变量必须是静态的。