我正在尝试从函数参数返回数据指针:
bool dosomething(char *data){
int datasize = 100;
data = (char *)malloc(datasize);
// here data address = 10968998
return 1;
}
但是当我按以下方式调用函数时,数据地址变为零:
char *data = NULL;
if(dosomething(data)){
// here data address = 0 ! (should be 10968998)
}
我究竟做错了什么？
希望你有一个美好的一天.
我正在开一个包装Berkley C Networking API的类,到目前为止我只有一个TCP服务器/客户端.
我具有讽刺意味的问题不是网络,而是堆栈和堆.也许我完全不理解它,但是当我使用类似的东西时:
ClientSocket *mysock = new ClientSocket();
并且只使用 - >运算符调用函数,它完全正常 - 如果发生错误,我的SocketException类没有被捕获.
但是,当我使用时:在使用
ClientSocket mysock;
函数调用函数时抛出任何异常.运营商,它显示:
terminate called after throwing an instance of 'SocketException'
Aborted
然后把我扔回终端提示.
忘了添加,我在try/catch块中包装调用.
我知道第一个例子是使用'new'关键字返回指向堆上新ClientSocket实例的指针,第二个示例是堆栈,但我不知道问题.
我在想我错过了关于指针/引用/堆栈/堆的东西,但我不知道发生了什么.代码经常运行得很好,但如果抛出任何异常....> :(
编辑:在链接页面上,Client.cxx和Server.cxx是示例文件!谢谢你指出这一点,埃里克.对此的帮助将不胜感激.这个项目的来源是:
所有文件的链接:http ://furryhead.co.cc/problem.html
(我无法粘贴超过2个链接,我有4个文件,所以这必须做到有人可以将链接合并到我的帖子中)注意:Socket.cxx相当大,因为它包含ServerSocket,ClientSocket和SocketException定义.
编译所有上述文件的命令是:
g ++ -c Socket.cxx -o Socket.o
g ++ -c Server.cxx -o Server.o
g ++ -c Client.cxx -o Client.o
g ++ Server.o Socket.o -o server
g ++ Client.o Socket.o -o client
谢谢!
根据Jon的建议,我没有更新,我查找了套接字函数的文档,它现在有更好的错误报告 - 我检查'errno'变量并基于此抛出异常.(那,我没有把它设置为非阻塞......;)) - 只是想更新并说声谢谢!:d
我最近不得不在rails上新安装ruby.当我尝试启动服务器以完成此新安装之前已经处理的项目时,我收到以下错误:
$ ruby script/server
=> Booting WEBrick...
./script/../config/../vendor/rails/railties/lib/rails/gem_dependency.rb:107:in `requirement': undefined method `version_requirements' for #<Gem::Dependency:0xb74bf764> (NoMethodError)
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:292:in `check_gem_dependencies'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:292:in `map'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:292:in `check_gem_dependencies'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:165:in `process'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:112:in `send'
from ./script/../config/../vendor/rails/railties/lib/initializer.rb:112:in `run'
from /media/78C0-455B/bidmc/schedule/config/environment.rb:13
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
from /media/78C0-455B/bidmc/schedule/vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
from /media/78C0-455B/bidmc/schedule/vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
from /media/78C0-455B/bidmc/schedule/vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
from /media/78C0-455B/bidmc/schedule/vendor/rails/railties/lib/commands/servers/webrick.rb:59
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
from /media/78C0-455B/bidmc/schedule/vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
from /media/78C0-455B/bidmc/schedule/vendor/rails/activesupport/lib/active_support/dependencies.rb:521:in `new_constants_in'
from /media/78C0-455B/bidmc/schedule/vendor/rails/activesupport/lib/active_support/dependencies.rb:153:in `require'
from /media/78C0-455B/bidmc/schedule/vendor/rails/railties/lib/commands/server.rb:49
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
from /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
from script/server:3
我有最新版本的ruby,rubygems和rails.
有什么建议？
谢谢.
我正在运行CentOS 5.5,我想在那里安装Haskell平台.根据haskell.org,CentOS根本不受支持(http://hackage.haskell.org/platform/linux.html).有谁知道是否可以在CentOS 5.5上设置Haskell？我在网上搜索但自己找不到任何相关信息.
我想压缩可能包含其他列表的列表,而不会破坏字符串.例如:
In [39]: list( itertools.chain(*["cat", ["dog","bird"]]) )
Out[39]: ['c', 'a', 't', 'dog', 'bird']
而且我想
['cat', 'dog', 'bird']
我想在我的网站上使用htmlpurifier,但无法弄清楚如何在视图中加载我的过滤器.我按照第一个答案中描述的方式添加了我的过滤器.
我希望能够从我的观点中调用它,比如$this->filter($content)任何建议我是怎么做到的？
我理解基本的二进制逻辑以及如何进行基本的加法,减法等.我得到的是,本文中的每个字符只是一个二进制数,表示字符集中的数字.这些数字对计算机来说并不意味着什么.然而,我很困惑计算机如何计算出一个数字大于另一个数字.它在比特级别做了什么？
当我将鼠标放在桌子的一个单元格上时,我想突出显示整条线!但是凭借我拥有的代码,我只能突出一个单元格!这是我的表:
<table id="myTable" class="tablesorter">
<thead>
<tr>
<th>Title1</th>
<th>Title2</th>
<th>Title3</th>
</tr>
</thead>
<tbody>
<tr>
<td>Bach</td>
<td>42526</td>
<td>Dec 10, 2002 5:14 AM</td>
</tr>
<tr>
<td>Doe</td>
<td>243155</td>
<td>Jan 18, 2007 9:12 AM</td>
</tr>
<tr>
<td>Conway</td>
<td>35263</td>
<td>Jan 18, 2001 9:12 AM</td>
</tr>
</tbody>
</table>
和css是
/*Table sort*/
table.tablesorter {
font-family:arial;
background-color: #e6EEEE;
font-size: 8pt;
width: 100%;
text-align: left;
}
table.tablesorter thead tr th, table.tablesorter tfoot tr th {
background-color: #e6EEEE;
border: 1px solid #FFF;
font-size: 8pt;
padding: 4px;
}
table.tablesorter thead tr .header …我正在阅读这篇文章,我正在尝试理解这个SQL语句,但我仍然对SQL有些新意.
我不确定评论和c是什么意思.
我认为其中一个是表名,但我不确定另一个.此外,显然其中有一个子查询,我没有任何经验:
SELECT c.id, c.user_id, c.body, c.deep, c.lineage, c.parent_id,
(SELECT COUNT(*)
FROM comment
WHERE comment.lineage LIKE (CONCAT(c.lineage,'%'))
AND comment.lineage != c.lineage) AS replies
FROM comment as c
ORDER BY c.lineage
摘要:
1.调试时手动进行类型转换,LachlanG和Ken指出.
2.利用自Delphi 2010以来引入的Debugger Visualizers概念
.3.切换到泛型对应物.
=========================================
以下面的代码为例:
如果断点分别设置在结束时TestRegular和结束时TestGenerics,可以通过调试检查器查看通用列表的项目(甚至是项目的内容),但没有任何意义(甚至不是计数)当一个人将鼠标悬停在tmp变量上时,常规的ashjectlist .我想知道是否有一些方法可以实现常规tobjectlist的类似调试时间功能？
unit Unit2;
interface
uses
Contnrs, Generics.Collections,
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs;
type
TMyItem = class;
TMyItemList = class;
TForm2 = class;
TMyItem = class
private
fname: string;
public
property name: string read fname;
constructor Create(aName: string);
end;
TMyItemList = class(TObjectList)
protected
procedure SetObject (Index: Integer; Item: TMyItem);
function GetObject (Index: Integer): TMyItem;
public
function Add (Obj: TMyItem): Integer;
procedure Insert …