《Windows 程序设计》程序4-2编译不通过的解决办法

为什么要这样定义呢，经“考证后”得到结论：  

#if WINVER>=0x0500

...

#define SM_MOUSEWHEELPRESENT ... //打个比方

...

#endif

 

所以如果没有定义WINVER或者WINVER<0x0500

#if WINVER>=0x0500

...

#endif

之间的代码就没有编译，也就是说这时编译器就看不到这些代码

所以要定义#define WINVER 0x0500 

看了这个稍微明白了点了 

编辑器是VC++6.0

建立 Win32 Application

 

在编译时出现如下错误：

 

--------------------Configuration: sysmets1 - Win32 Debug--------------------

Compiling...

sysmets1.c

e:"test"sysmets1"sysmets.h(297) : error C2065: 'SM_MOUSEWHEELPRESENT' : undeclared identifier

e:"test"sysmets1"sysmets.h(297) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(297) : warning C4047: 'initializing' : 'int ' differs in levels of indirection from 'char [21]'

e:"test"sysmets1"sysmets.h(301) : error C2065: 'SM_XVIRTUALSCREEN' : undeclared identifier

e:"test"sysmets1"sysmets.h(301) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(303) : warning C4047: 'initializing' : 'int ' differs in levels of indirection from 'char [24]'

e:"test"sysmets1"sysmets.h(305) : error C2065: 'SM_YVIRTUALSCREEN' : undeclared identifier

e:"test"sysmets1"sysmets.h(305) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(309) : error C2065: 'SM_CXVIRTUALSCREEN' : undeclared identifier

e:"test"sysmets1"sysmets.h(309) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(309) : warning C4047: 'initializing' : 'int ' differs in levels of indirection from 'char [19]'

e:"test"sysmets1"sysmets.h(313) : error C2065: 'SM_CYVIRTUALSCREEN' : undeclared identifier

e:"test"sysmets1"sysmets.h(313) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(315) : warning C4047: 'initializing' : 'int ' differs in levels of indirection from 'char [22]'

e:"test"sysmets1"sysmets.h(317) : error C2065: 'SM_CMONITORS' : undeclared identifier

e:"test"sysmets1"sysmets.h(317) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(321) : error C2065: 'SM_SAMEDISPLAYFORMAT' : undeclared identifier

e:"test"sysmets1"sysmets.h(321) : error C2099: initializer is not a constant

e:"test"sysmets1"sysmets.h(321) : warning C4047: 'initializing' : 'int ' differs in levels of indirection from 'char [21]'

Error executing cl.exe.

 

sysmets1.obj - 14 error(s), 5 warning(s)

 

解决方法：

 

那些是WindowNT里才能使用的常量，它是是被条件编译的。

需要在的sysmets.cpp文件的最前面加一句

#define WINVER 0x0500

 

Minimum System Required Macros to Define

Windows 95 and

Windows NT 4.0 WINVER=0x0400

Windows 98 and

Windows NT 4.0 _WIN32_WINDOWS=0x0410 and WINVER=0x0400

Windows NT 4.0 _WIN32_WINNT=0x0400 and WINVER=0x0400

Windows 98 _WIN32_WINDOWS=0x0410

Windows 2000 _WIN32_WINNT=0x0500 and WINVER=0x0500

Windows Me _WIN32_WINDOWS=0x049