subject_24019.htm

一些关于vc的问答

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序号：24019 发表者：xiongli 发表日期：2002-12-08 21:58:02
<br>主题：几个才遇上的c/c++问题，关于内存泄漏的检测和__try
<br>内容：#define _CRTDBG_MAP_ALLOC<BR>#include &lt;stdlib.h&gt;<BR>#include &lt;crtdbg.h&gt;<BR>#include &lt;iostream&gt;<BR>#include &lt;vector&gt;<BR>#include &lt;algorithm&gt;<BR>using namespace std;<BR><BR>int k(void (*d)())<BR>{<BR>&nbsp;&nbsp;&nbsp;&nbsp;d();<BR>&nbsp;&nbsp;&nbsp;&nbsp;return 0;<BR>}<BR>void j(void (*d)())<BR>{<BR>&nbsp;&nbsp;&nbsp;&nbsp;d();<BR>}<BR>void test()<BR>{<BR>&nbsp;&nbsp;&nbsp;&nbsp;cout &lt;&lt;0;<BR>}<BR>int main()<BR>{<BR>//&nbsp;&nbsp;&nbsp;&nbsp;int *jkm=(int*)malloc(sizeof(int));<BR>/*&nbsp;&nbsp;&nbsp;&nbsp;void (*p)(void (*)());<BR>&nbsp;&nbsp;&nbsp;&nbsp;p=j;<BR>&nbsp;&nbsp;&nbsp;&nbsp;j(test);<BR>&nbsp;&nbsp;&nbsp;&nbsp;int (*pp)(void (*)());<BR>&nbsp;&nbsp;&nbsp;&nbsp;pp=k;<BR>&nbsp;&nbsp;&nbsp;&nbsp;p(test);*/<BR>&nbsp;&nbsp;&nbsp;&nbsp;_CrtDumpMemoryLeaks();<BR>&nbsp;&nbsp;&nbsp;&nbsp;return 0;<BR>}<BR><BR>以上是一段随便写的代码，按照msdn,这样可以dump出malloc造成的memory leak．但是我再main里面直接return,debug里面居然显示<BR><BR>Loaded 'C:\WINNT\System32\ntdll.dll', no matching symbolic information found.<BR>Loaded 'C:\WINNT\system32\KERNEL32.DLL', no matching symbolic information found.<BR>Detected memory leaks!<BR>Dumping objects -&gt;<BR>c:\program files\microsoft visual studio\vc98\include\crtdbg.h(552) : {62} normal block at 0x004815A0, 33 bytes long.<BR> Data: &lt; C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&gt; 00 43 00 CD CD CD CD CD CD CD CD CD CD CD CD CD <BR>c:\program files\microsoft visual studio\vc98\include\crtdbg.h(552) : {61} normal block at 0x004815F0, 40 bytes long.<BR> Data: &lt;t F&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &gt; 74 B2 46 00 16 00 00 00 00 00 00 00 00 00 00 00 <BR>Object dump complete.<BR>The thread 0x514 has exited with code 0 (0x0).<BR>The program 'C:\Documents and Settings\Administrator\桌面\subject_1_19199\Debug\node_lev.exe' has exited with code 0 (0x0).<BR><BR><BR>说有内存泄漏．这是第一个不解<BR>同时我想问，在c++／vc++里面如何检查new造成的内存泄漏．我在msdn上看到一些方法，比如用<BR>CMemoryState<BR>但是我记得我以前看到过一种简单dump的方法，也是前面include，然后好像要define new __new的．能给一个例子吗？？<BR><BR>第三个问题．常常看到一些关键字前面有__.比如__int 32　　__try __catch等等．我想问一下，这代表什么？？<BR>谢谢
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回复者：混混 回复日期：2002-12-08 22:16:14
<br>内容：这部分提示就是dump出的泄漏(没有free)<BR>c:\program files\microsoft visual studio\vc98\include\crtdbg.h(552) : {62} normal block at 0x004815A0, 33 bytes long.<BR>Data: &lt; C&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&gt; 00 43 00 CD CD CD CD CD CD CD CD CD CD CD CD CD <BR>c:\program files\microsoft visual studio\vc98\include\crtdbg.h(552) : {61} normal block at 0x004815F0, 40 bytes long.<BR>Data: &lt;t F&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &gt; 74 B2 46 00 16 00 00 00 00 00 00 00 00 00 00 00 <BR><BR>CMemoryState 我不知道,<BR><BR>加__好像是在支持标准c++的同时,搞点微软的特色<BR><BR>2002-12-8 22:18:37