error LNK2019: unresolved external symbol __imp_

Hi, I am facing an issue while generating the mex file for a S function in MATLAB 2012b. But the mex file generation in Matlab 2012b 64 bit is showing the following error. And the .pdb file is not generated.

>> mex virtual_bus_sfun.c
Your MATLAB session has timed out.  All license keys have been returned.
   Creating library C:\Users\knilayan\AppData\Local\Temp\mex_VZ4CKa\templib.x and object C:\Users\knilayan\AppData\Local\Temp\mex_VZ4CKa\templib.exp 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_signal referenced in function mdlOutputs 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_update referenced in function mdlOutputs 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_reset referenced in function mdlOutputs 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_wait referenced in function mdlOutputs 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_delete referenced in function mdlStart 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_connect referenced in function mdlStart 
virtual_bus_sfun.obj : error LNK2019: unresolved external symbol __imp_virtual_bus_disconnect referenced in function mdlTerminate 
virtual_bus_sfun.mexw64 : fatal error LNK1120: 7 unresolved externals 

    C:\PROGRA~1\MATLAB\R2012B\BIN\MEX.PL: Error: Link of 'virtual_bus_sfun.mexw64' failed.

The mentioned “external symbols” in error message are declared in the header file “Virtual_Bus.h”. Both the header files “Virtual_Bus.h” is present in the MATLAB path. It would be really great if someone could help me out with this linker error.

Virtual_Bus.h:

#ifndef VIRTUAL_BUS_H
#define VIRTUAL_BUS_H

/* DLL boilerplate code */
#ifdef VIRTUAL_BUS_EXPORTS
#define VIRTUAL_BUS_API __declspec(dllexport)
#else
#define VIRTUAL_BUS_API __declspec(dllimport)
#endif
#include "Virtual_Bus_Types.h"
#ifdef __cplusplus
extern "C"
{
#endif

VIRTUAL_BUS_API struct Virtual_Bus_Data* virtual_bus_connect(
    char* const bus_name);

/**     @brief Disconnect from a virtual bus
 *
 *     Disconnects from a virtual bus identified by the specified pointer.
 *
 *     @param bus_data = Virtual_Bus_Data* structure
 *     @return Virtual_Bus_Error_Code error code type
 */

[Sebastian Schulte]

Hi,

I guess it's a x64/x32 issue. You build templib.x with a 32 bit compiler, right?

Best greetings Sebastian