VC6环境下USB编程链接错误解决办法

VC6环境下USB编程链接错误解决办法

背景介绍：

编程环境：Visual C++ 6.0 + SP6

操作系统：Windows XP Service Pack 3

提出问题：

在MFC应用程序中引用经典的USBView源码过程中，出现如下错误：

usb.obj : error LNK2001: unresolved external symbol "unsigned long __stdcall CM_Get_Parent(unsigned long *,unsigned long,unsigned long)" (?CM_Get_Parent@@YGKPAKKK@Z)

usb.obj : error LNK2001: unresolved external symbol "unsigned long __stdcall CM_Get_Sibling(unsigned long *,unsigned long,unsigned long)" (?CM_Get_Sibling@@YGKPAKKK@Z)

usb.obj : error LNK2001: unresolved external symbol "unsigned long __stdcall CM_Get_Child(unsigned long *,unsigned long,unsigned long)" (?CM_Get_Child@@YGKPAKKK@Z)

usb.obj : error LNK2001: unresolved external symbol "unsigned long __stdcall CM_Get_DevNode_Registry_PropertyA(unsigned long,unsigned long,unsigned long *,void *,unsigned long *,unsigned long)" (?CM_Get_DevNode_Registry_PropertyA@@YGKKKPAKPAX0K@

Z)

usb.obj : error LNK2001: unresolved external symbol "unsigned long __stdcall CM_Locate_DevNodeA(unsigned long *,char *,unsigned long)" (?CM_Locate_DevNodeA@@YGKPAKPADK@Z)

../bin/Debug/ATSync.exe : fatal error LNK1120: 5 unresolved externals

分析问题：

CM_Locate_DevNode

CM_Get_DevNode_Registry_Property

CM_Get_Sibling

CM_Get_Child

CM_Get_Parent

这些函数都来自于同一个cfgmgr32.lib静态链接库中，

而cfgmgr32.lib库应该是使用C语言进行编译的，所以在使用C++进行编程时，在引用cfgmgr32.h头文件时不能简单地使用include，即#include "cfgmgr32.h"，而需要加入extern “C”的声明。

解决问题：

#ifdef __cplusplus

extern "C"{

#include "cfgmgr32.h"

}

#endif