IsDeclared无法检查变量是否已经声明

smooth

我脚本用先插入#include <WindowsConstants.au3>这个头文件，其中里面声明了4个变量：
[au3]
Global Const $WM_COMMAND = 0x0111
Global Const $WM_MOVE = 0x0003
Global Const $WM_LBUTTONDOWN = 0x0201
Global Const $WM_RBUTTONDOWN = 0x0204
[/au3]
在WindowsConstants.au3的后面，还插入了GUIInputSetOnlyNumbers.au3这个头文件，其中声明了上述4个变量，不过声明的方式如下：
[au3]
If Not IsDeclared("WM_COMMAND")                 Then Global Const $WM_COMMAND                = 0x0111
If Not IsDeclared("WM_MOVE")                        Then Global Const $WM_MOVE               = 0x0003
If Not IsDeclared("WM_LBUTTONDOWN")         Then Global Const $WM_LBUTTONDOWN         = 0x0201
If Not IsDeclared("WM_RBUTTONDOWN")         Then Global Const $WM_RBUTTONDOWN         = 0x0204
[/au3]

查了一下IsDeclared函数的作用，是检查某个变量是否已经声明过了，没声明过的话则声明某个变量。可是虽然如此，我的脚本还是无法执行，提示如下错误信息：

1. 
   
2. D:\Program Files\autoit3\Include\GUIInputSetOnlyNumbers.au3(4,74) : ERROR: $WM_COMMAND previously declared as a 'Const'
   
3. If Not IsDeclared("WM_COMMAND")                 Then Global Const $WM_COMMAND                = 0x0111
   
4. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                ~~~~~~~~^
   
5. D:\Program Files\autoit3\Include\GUIInputSetOnlyNumbers.au3(5,70) : ERROR: $WM_MOVE previously declared as a 'Const'
   
6. If Not IsDeclared("WM_MOVE")                        Then Global Const $WM_MOVE                         = 0x0003
   
7. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~                        ~~~~~~~~^
   
8. D:\Program Files\autoit3\Include\GUIInputSetOnlyNumbers.au3(6,81) : ERROR: $WM_LBUTTONDOWN previously declared as a 'Const'
   
9. If Not IsDeclared("WM_LBUTTONDOWN")         Then Global Const $WM_LBUTTONDOWN         = 0x0201
   
10. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~        ~~~~~~~~^
    
11. D:\Program Files\autoit3\Include\GUIInputSetOnlyNumbers.au3(7,81) : ERROR: $WM_RBUTTONDOWN previously declared as a 'Const'
    
12. If Not IsDeclared("WM_RBUTTONDOWN")         Then Global Const $WM_RBUTTONDOWN         = 0x0204
    

复制代码

这究竟是为什么呢？如果在插入头文件的顺序上，是先插入GUIInputSetOnlyNumbers.au3，再插入WindowsConstants.au3，那提示错误好像还好理解。
谢谢！

afan

AU3Check.exe 对 IsDeclared 类函数不会识别，可以无视之。

netegg

看英文，已经声明为全局常量了，不能重新声明

zhouflye

好东东，学习了！

smooth

回复 2# afan
原来如此，谢谢！