DWORD_PTR没有定义。怎么回事？

[不懂必须要问]

我是用SDK，做着RichEdit这个控件的时候。

搜索整个VS的目录，没有发现“DWORD_PTR”这个数据类型，但在MSDN中发现了。

EditStreamCallback
The EditStreamCallback function is an application defined–callback function used with the EM_STREAMIN and EM_STREAMOUT messages. It is used to transfer a stream of data into or out of a rich edit control. The EDITSTREAMCALLBACK type defines a pointer to this callback function. EditStreamCallback is a placeholder for the application defined–function name.

DWORD CALLBACK EditStreamCallback(
DWORD_PTR dwCookie, // application-defined value
LPBYTE pbBuff, // data buffer
LONG cb, // number of bytes to read or write
LONG *pcb // number of bytes transferred
);
Parameters
dwCookie
[in] Value of the dwCookie member of the EDITSTREAM structure. The application specifies this value when it sends the EM_STREAMIN or EM_STREAMOUT message.
pbBuff
[in] Pointer to a buffer to read from or write to. For a stream-in (read) operation, the callback function fills this buffer with data to transfer into the rich edit control. For a stream-out (write) operation, the buffer contains data from the control that the callback function writes to some storage.
cb
[in] Number of bytes to read or write.
pcb
[in] Pointer to a variable that the callback function sets to the number of bytes actually read or written.

[zoulie]

没包含就自己申明一下，其实就是一个int32或者int64的指针

[bigriverhorse]

SDK有自己一套定义，不要搜索VS目录，去SDK目录搜索吧。

[雪影]

This type is declared in BaseTsd.h as follows:

typedef ULONG_PTR DWORD_PTR;

[sunlin7]

DWORD_PTR是为了和64位兼容的。
在win32里面可以直接
typedef DWORD DWORD_PTR;
或
#define DWORD_PTR DWORD