未解决的外部符号错误，即使已定义功能并被IDE看到也是如此

Question

using Visual C++ 2008, I am having an "Unresolved external symbol" even if with the IDE I can correctly see both declaration and definition of the function:

The error:

hook_file.obj : error LNK2001: unresolved external symbol "int __cdecl is_directory_objattr(struct _OBJECT_ATTRIBUTES const *)" (?is_directory_objattr@@YAHPBU_OBJECT_ATTRIBUTES@@@Z)

Relevant code in hook_file.cpp:

    #include "misc.h"

    void handle_new_file(HANDLE file_handle, const OBJECT_ATTRIBUTES *obj)
        {
            if(is_directory_objattr(obj) == 0 ) { 
            // etc.

Declaration in misc.h file:

BOOL is_directory_objattr(const OBJECT_ATTRIBUTES *obj);

Definition in misc.cpp file:

#include "misc.h"

BOOL is_directory_objattr(const OBJECT_ATTRIBUTES *obj)
    { //function body here }

I really don't get what the linker has to complain here.

• The header with function declaration is included by the file which calls the function.
• The cpp file with the function definition included header file with declaration.
• Declaration and definitions are identical.
• All files are listed among project files.

Any idea whats wrong?

Thanks!

Answer 1

Have you only include one time your header file?

in misc.h

#ifndef MISC
#define MISC

...

#endif MISC ?