HANDLE_##message是什么啊,高手帮忙啊

[jronald]

BOOL WINAPI Dlg_Proc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {

switch (uMsg) {
chHANDLE_DLGMSG(hwnd, WM_INITDIALOG, Dlg_OnInitDialog);
chHANDLE_DLGMSG(hwnd, WM_SIZE, Dlg_OnSize);
chHANDLE_DLGMSG(hwnd, WM_COMMAND, Dlg_OnCommand);
}
return(FALSE);
}

#define chHANDLE_DLGMSG(hwnd, message, fn) \
case (message): return (SetDlgMsgResult(hwnd, uMsg, \
HANDLE_##message((hwnd), (wParam), (lParam), (fn))))

#define SetDlgMsgResult(hwnd, msg, result) (( \
(msg) == WM_CTLCOLORMSGBOX || \
(msg) == WM_CTLCOLOREDIT || \
(msg) == WM_CTLCOLORLISTBOX || \
(msg) == WM_CTLCOLORBTN || \
(msg) == WM_CTLCOLORDLG || \
(msg) == WM_CTLCOLORSCROLLBAR || \
(msg) == WM_CTLCOLORSTATIC || \
(msg) == WM_COMPAREITEM || \
(msg) == WM_VKEYTOITEM || \
(msg) == WM_CHARTOITEM || \
(msg) == WM_QUERYDRAGICON || \
(msg) == WM_INITDIALOG \
) ? (BOOL)(result) : (SetWindowLong((hwnd), DWL_MSGRESULT, (LPARAM)(LRESULT)(result)), TRUE))

chHANDLE_DLGMSG宏定义中怎么冒出一个uMsg，是不是对应Dlg_Proc的第二个参数，其实uMsg和message的值不是一样吗？用message不是更好？否则Dlg_Proc的第二个参数一定要取名为uMsg了？不知道是不是书的作者的不小心？
HANDLE_##message被替换成HANDLE_WM_INITDIALOG等东西后，根本查不到这些东西是什么。

[enoloo]

就是预编译的时候，用##后面的值和前面的部分连接起来。

比如
#define a(handle) class##handle

那么，程序中a(5),就会转换成class5.

[enoloo]

msdn这么解释的,
The double-number-sign or “token-pasting” operator (##), which is sometimes called the “merging” operator, is used in both object-like and function-like macros. It permits separate tokens to be joined into a single token and therefore cannot be the first or last token in the macro definition.

[jronald]

是啊，但是连起来后，比如是HANDLE_WM_INITDIALOG，不知道这个是什么东西

[jronald]

UPUP

[ANewGuy]

顶

[kuangjingbo]

连接符号，就是跟后面的
enoloo(行者无疆)的例子很好

[redmoons]

如果你真的想看到HANDLE_##message被替换成HANDLE_WM_INITDIALOG后的东东，ALT＋F8变成汇编就看到了，不过很费神，但对于问题应该很容易就明白了，你的第一个问题，也可以这样的。如果我说错了，还请大家多多批评。