Solution to USB programming Link error in vc6 Environment

Vc6Solution to USB programming Link error in Environment

Background:

Programming Environment: Visual C ++ 6.0 + SP6

Operating System: Windows XP Service Pack 3

Raise questions:

The following error occurs when you reference the classic USB view source code in an MFC application:

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 equals (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

Analyze the problem:

Cm_locate_devnode

Cm_get_devnode_registry_property

Cm_get_sibling

Cm_get_child

Cm_get_parent

These functions are all from the same cfgmgr32.lib static Link Library,

The cfgmgr32.lib library should be compiled in C language. Therefore, when using C ++ for programming, you cannot simply use include When referencing the cfgmgr32.h header file, that is, # include "cfgmgr32.h ", the extern "C" statement must be added.

Solution:

# Ifdef _ cplusplus

Extern "C "{

# Include "cfgmgr32.h"

}

# Endif