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Tess — Tue, 03 Nov 2009 14:53:00 GMT

最�q�发现CRT控制台程序没有TRACE和内存溢出检查，很郁闗��无聊中��ȝ��MSDN的Memory Management and the Debug Heap��，发现C的Debug版本用_malloc_dbg代替malloc,而_malloc_dbg者给数据堆加上一个控制头�l�成链表�Q�方便记录溢出。原话如下：
When you request a memory block, the debug heap manager allocates from the base heap a slightly larger block of memory than requested and returns a pointer to your portion of that block. For example, suppose your application contains the call: malloc( 10 ). In a release build, malloc would call the base heap allocation routine requesting an allocation of 10 bytes. In a debug build, however, malloc would call _malloc_dbg, which would then call the base heap allocation routine requesting an allocation of 10 bytes plus approximately 36 bytes of additional memory. All the resulting memory blocks in the debug heap are connected in a single linked list, ordered according to when they were allocated:
那个控制头的数据�l�构如下�Q?br>

typedef struct _CrtMemBlockHeader
{
// Pointer to the block allocated just before this one:
   struct _CrtMemBlockHeader *pBlockHeaderNext;
// Pointer to the block allocated just after this one:
   struct _CrtMemBlockHeader *pBlockHeaderPrev;
   char *szFileName;   // File name
   int nLine;          // Line number
   size_t nDataSize;   // Size of user block
   int nBlockUse;      // Type of block
   long lRequest;      // Allocation number
// Buffer just before (lower than) the user's memory:
   unsigned char gap[nNoMansLandSize];
} _CrtMemBlockHeader;

�q�个nBlockUse�?�U�内存块�Q�具体含义还没有搞清楚，分别如下

/* Memory block identification */
#define _FREE_BLOCK      0
#define _NORMAL_BLOCK    1
#define _CRT_BLOCK       2
#define _IGNORE_BLOCK    3
#define _CLIENT_BLOCK    4
#define _MAX_BLOCKS      5

��内存溢出用_CrtDumpMemoryLeaks(),�?span style="font-weight: bold;">crtdbg.h中定义。有旉��研究一下crtdbg.h文�g�?br> 参�?a >http://www.cnblogs.com/phinecos/archive/2009/10/29/1592604.html

Tess 2009-11-03 22:53 发表评论

Tess — Tue, 20 Oct 2009 14:36:00 GMT

《window�E�序设计》果然是�l�典�Q�相对于MFC来说SDK��直是�q�璞归真啊。��l�摘录一些API函数和技巧：

CheckRadioButton(hwnd,IDC_SERVER1,IDC_SERVER10, wServer);

1�?font>Selects (adds a check mark to) a given radio button in a group and clears (removes a check mark from) all other radio buttons in the group. 在IDC_SERVER1-IDC_SERVER10中选中wServer的ID�Q�有点像分组�?br>

DialogBoxParam (hInst, TEXT ("Servers"), hwnd, ServerDlg, (LPARAM) szIPAddr);

2、可以在WM_INITDIALOG的LPARAM传参敎ͼ�建立模态对话框。ServerDlg为消息处理函敎ͼ�szIPAddr为参敎ͼ�在WM_INITDIALOG消息响应中处理LPARAM的倹{�?br>

typedef char * va_list;

#define _INTSIZEOF(n)   ( (sizeof(n) + sizeof(int) - 1) & ~(sizeof(int) - 1) )
#define va_start(ap,v)  ( ap = (va_list)&v + _INTSIZEOF(v) )
#define va_arg(ap,t)    ( *(t *)((ap += _INTSIZEOF(t)) - _INTSIZEOF(t)) )
#define va_end(ap)      ( ap = (va_list)0 )

3、va_list可变参数的结构，有点复杂慢慢看�?br> 一般的用法是这�?个�h理解)
va_list args; //声明变量
va_start(args, fmt); //开始解析。args指向fmt后面的参�?
TYPE var = va_arg(args, TYPE); //取下一个参数�ƈ�q�回。args指向下一个参�?
va_end(args); //�l�束解析
http://hi.baidu.com/kang_liang/blog/item/168c9059a9a1ca2d2934f05f.html

4、wsprintf和wvsprintf的区别，从它们的参数可以看出�?br>

int wsprintf(
  LPTSTR lpOut,    // output buffer
  LPCTSTR lpFmt,   // format-control string
                // optional arguments
);

int wvsprintf( LPTSTR lpOutput, // buffer for output
               LPCTSTR lpFormat, // format-control string
               va_list // variable list of format-control arguments
   );

wsprintf�U��a是格式化字符�Ԍ��wvsprintf是以参数列表Va_list格式化字�W�串�?/p>

Tess 2009-10-20 22:36 发表评论

Tess — Mon, 19 Oct 2009 15:05:00 GMT

最�q�看Petzold的《windows�E�序设计》，在Internet那章中看到如何在字符串中提取IP地址�Q�特地标��C��下：

1 GetDlgItemTextA (hwnd, wServer, szLabel, sizeof (szLabel));
2 strtok (szLabel, "(");
3 strcpy (szServer, strtok (NULL, ")"));

在Msdn上查了一下，有下面一�D�：

On the first call to strtok , the function skips leading delimiters and returns a pointer to the first token in strToken , terminating the token with a null character. More tokens can be broken out of the remainder of strToken by a series of calls to strtok . Each call to strtok modifies strToken by inserting a null character after the token returned by that call. To read the next token from strToken , call strtok with a NULL value for the strToken argument. The NULL strToken argument causes strtok to search for the next token in the modified strToken . The strDelimit argument can take any value from one call to the next so that the set of delimiters may vary.

Warning Each of these functions uses a static variable for parsing the string into tokens. If multiple or simultaneous calls are made to the same function, a high potential for data corruption and inaccurate results exists. Therefore, do not attempt to call the same function simultaneously for different strings and be aware of calling one of these function from within a loop where another routine may be called that uses the same function. However, calling this function simultaneously from multiple threads does not have undesirable effects.

看来用了静态变量，�q�好有多�U�程的C�q�行库，否则在多�U�程在有�ȝ��了�?br>

Tess 2009-10-19 23:05 发表评论