Linker error when creating Mex file

I am running Windows 7-64 bit with MatlabR2013a(64bit) using Microsoft VSC++2012. I am getting a linker error (LNK2019) when trying to create a mex file. I am using functions that are contained in a library file to which I have tried my best to tell the compiler where it is. I have no problem compiling and running my code in an environment outside Matlab.

I have tried every variation of:

mex foo.cpp thelibrary.lib ...

mex foo.cpp -l'thelibrary' -L'\thelibrarydirectory' ...

mex foo.cpp -lthelibrary -L\thelibrarydirectory ...

that I can think of, and none of them work. The error message that I get is pasted below. Any insight would be appreciated.

{

-> Default options filename found in C:\Users\David\AppData\Roaming\MathWorks\MATLAB\R2013a ---------------------------------------------------------------- -> Options file =

C:\Users\David\AppData\Roaming\MathWorks\MATLAB\R2013a\mexopts.bat

      MATLAB                 = C:\Program Files\MATLAB\R2013a

-> COMPILER = cl

-> Compiler flags:

         COMPFLAGS           = /c /GR /W3 /EHs /D_CRT_SECURE_NO_DEPRECATE 
/D_SCL_SECURE_NO_DEPRECATE /D_SECURE_SCL=0 /DMATLAB_MEX_FILE /nologo /MD 

         OPTIMFLAGS          = /O2 /Oy- /DNDEBUG 

         DEBUGFLAGS          = /Z7 

         arguments           =  -I"C:\Program Files (x86)\Thorlabs\DCx Cameras\Develop\include" 

         Name switch         = /Fo

-> Pre-linking commands =

-> LINKER = link

-> Link directives:

         LINKFLAGS           = /dll /export:mexFunction /LIBPATH:"C:\Program Files\MATLAB\R2013a\extern\lib\win64\microsoft" libmx.lib libmex.lib libmat.lib /MACHINE:X64 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /manifest /incremental:NO /implib:"C:\Users\David\AppData\Local\Temp\mex_XumyOA\templib.x" 
/MAP:"mqueryinfo.mexw64.map" 

         LINKDEBUGFLAGS      = /debug /PDB:"mqueryinfo.mexw64.pdb" 

         LINKFLAGSPOST       =  

         Name directive      = /out:"mqueryinfo.mexw64" 

         File link directive =  

         Lib. link directive =  

         Rsp file indicator  = @

-> Resource Compiler = rc /fo "mexversion.res"

-> Resource Linker =

----------------------------------------------------------------

--> cl -I"C:\Program Files (x86)\Thorlabs\DCx Cameras\Develop\include" /c /GR /W3 /EHs /D_CRT_SECURE_NO_DEPRECATE /D_SCL_SECURE_NO_DEPRECATE /D_SECURE_SCL=0 /DMATLAB_MEX_FILE /nologo /MD /FoC:\Users\David\AppData\Local\Temp\mex_XumyOA\mqueryinfo.obj -I"C:\Program Files\MATLAB\R2013a\extern\include" -I"C:\Program Files\MATLAB\R2013a\simulink\include" /O2 /Oy- /DNDEBUG -DMX_COMPAT_32 mqueryinfo.cpp

mqueryinfo.cpp mqueryinfo.cpp(131) : warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' (performance warning) mqueryinfo.cpp(132) : warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' (performance warning) mqueryinfo.cpp(133) : warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' (performance warning) mqueryinfo.cpp(134) : warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' (performance warning) mqueryinfo.cpp(135) : warning C4800: 'BOOL' : forcing value to bool 'true' or 'false' (performance warning) mqueryinfo.cpp(34) : warning C4101: 'jstruct' : unreferenced local variable mqueryinfo.cpp(36) : warning C4101: 'ndim' : unreferenced local variable mqueryinfo.cpp(37) : warning C4101: 'tmp' : unreferenced local variable mqueryinfo.cpp(35) : warning C4101: 'NStructElems' : unreferenced local variable mqueryinfo.cpp(33) : warning C4101: 'classIDflags' : unreferenced local variable mqueryinfo.cpp(37) : warning C4101: 'fout' : unreferenced local variable c:\users\david\documents\thorlabs\matlab files\mqueryinfo.cpp(84) : warning C4700: uninitialized local variable 'nfields' used Contents of C:\Users\David\AppData\Local\Temp\mex_XumyOA\mex_tmp.rsp: C:\Users\David\AppData\Local\Temp\mex_XumyOA\mqueryinfo.obj uc480.lib

--> link /out:"mqueryinfo.mexw64" /dll /export:mexFunction /LIBPATH:"C:\Program Files\MATLAB\R2013a\extern\lib\win64\microsoft" libmx.lib libmex.lib libmat.lib /MACHINE:X64 kernel32.lib user32.lib gdi32.lib winspool.lib comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib uuid.lib odbc32.lib odbccp32.lib /nologo /manifest /incremental:NO /implib:"C:\Users\David\AppData\Local\Temp\mex_XumyOA\templib.x" /MAP:"mqueryinfo.mexw64.map" @C:\Users\David\AppData\Local\Temp\mex_XumyOA\mex_tmp.rsp "C:\Program Files\MATLAB\R2013a\extern\lib\win64\microsoft\uc480.lib"

   Creating library C:\Users\David\AppData\Local\Temp\mex_XumyOA\templib.x and object C:\Users\David\AppData\Local\Temp\mex_XumyOA\templib.exp 
mqueryinfo.obj : error LNK2019: unresolved external symbol __imp_is_InitCamera referenced in function mexFunction 
mqueryinfo.obj : error LNK2019: unresolved external symbol __imp_is_ExitCamera referenced in function mexFunction 
mqueryinfo.obj : error LNK2019: unresolved external symbol __imp_is_GetNumberOfCameras referenced in function mexFunction 
mqueryinfo.obj : error LNK2019: unresolved external symbol __imp_is_GetSensorInfo referenced in function mexFunction 
mqueryinfo.obj : error LNK2019: unresolved external symbol __imp_is_GetCameraList referenced in function mexFunction 
mqueryinfo.mexw64 : fatal error LNK1120: 5 unresolved externals 

C:\PROGRA~1\MATLAB\R2013A\BIN\MEX.PL: Error: Link of 'mqueryinfo.mexw64' failed.

Error using mex (line 206) Unable to complete successfully. }

EDIT: SOLVED when I specified a 64 bit library instead.

[Kaustubha Govind]

Please add your solution as an "Answer" and accept it, so it is clear that this issue is resolved.

[Camilla]

Hi David, I am having the same your problem. I am trying to call functions that are defined in a DLL but when I try to compile my main.cpp with matlab compiler I have the error LNK2019: unresolved external symbol

Were you able to solve the problem? If so, please let me know...I am having hard time with that!

[Kaustubha Govind]

Camilla: David posted his solution at the bottom of his question, as an EDIT.

[Camilla]

Thanks, I will try his solution immediately

[George]

HOW and WHERE do you specify the 64-bit library?