Import dll

Question

I am trying to import a dll. All of it. I will need almost all of the functions. I have tried using the Import Library Function Node, but I realized that it is very time consuming. Also, there are functions spanning too many different header files. so I am trying to use Tools -> Import -> Shared Library (.dll). I get stuck with preprocessor directives. I am posting step by step:
The message for the first function is:
The function cannot be imported into LabVIEW. This might be caused by one of the following problems:
The function is not declared in the header file but is exported in the library.
Check the header file to make sure it contains declarations of the function.
Undefined symbols can prevent the wizard from recognizing functions and parameters. To correct this problem, check the header file to determine if you must add preprocessor definitions. Click the Back button to return to the previous page of the wizard to add a preprocessor definitionsl (for example, "NIAPI_stdcall = __stdcall" or "NIAPIDefined = 1").
GENAPIC_EXPORTS;GENAPIC_LINUX_BUILD;GENAPIC_WIN_BU​ILD;MIDL_PASS;MRTDLL;PYLONC_BOOL_DEFINED;PYLONC_EX​PORTS;RC_INVOKED;UNALIGNED;_CRTDBG_MAP_ALLOC;_CRT_​ALIGN;_CRT_ALTERNATIVE_INLINES;_CRT_DISABLE_PERFCR​IT_LOCKS;_CRT_FORCE_MANIFEST;_CRT_GETPUTWCHAR_NOIN​LINE;_CRT_MANAGED_HEAP_NO_DEPRECATE;_CRT_MANAGED_H​EAP_NO_WARNINGS;_CRT_MANIFEST_DEBUG;_CRT_MANIFEST_​INCONSISTENT;_CRT_MANIFEST_RETAIL;_CRT_NOFORCE_MAN​IFEST;_CRT_NONSTDC_DEPRECATE;_CRT_NONSTDC_NO_DEPRE​CATE;_CRT_NONSTDC_NO_WARNINGS;_CRT_NON_CONFORMING_​SWPRINTFS;_CRT_OBSOLETE_NO_DEPRECATE;_CRT_OBSOLETE​_NO_WARNINGS;_CRT_SECURE_CPP_OVERLOAD_SECURE_NAMES​;_CRT_SECURE_CPP_OVERLOAD_STANDARD_NAMES;_CRT_SECU​RE_CPP_OVERLOAD_STANDARD_NAMES_COUNT;_CRT_SECURE_D​EPRECATE_MEMORY;_CRT_SECURE_NO_DEPRECATE;_CRT_SECU​RE_NO_DEPRECATE_GLOBALS;_CRT_SECURE_NO_WARNINGS;_C​RT_SECURE_NO_WARNINGS_GLOBALS;_CRT_SECURE_WARNINGS​_MEMORY;_DEBUG;_DLL;_MSC_EXTENSIONS;_MSC_VER;_MSC_​VER_GREATER_THEN_13102050;_MT;_M_AMD64;_M_CEE;_M_C​EE_MIXED;_M_CEE_PURE;_M_IA64;_M_IX86;_PFT_SHOULD_C​HECK_RETURN;_PFT_SHOULD_CHECK_RETURN_WAT;_PFT_VER;​_POSIX_;_PREFAST_;_STATIC_CPPLIB;_TRUNCATE;_USE_32​BIT_TIME_T;_USE_ATTRIBUTES_FOR_SAL;_VC_NODEFAULTLI​B;_W64;_WIN32;_WIN64;_X86_;__BORLANDC__;__CRTDECL;​__GNUC__;__cdecl;__cplusplus;__cplusplus_cli;__lin​ux__;__midl;
Most of these should be undefined. For example, there is:
#ifdef GENAPIC_EXPORTS
//do A
#else
//do B
And I want it to do B. But this is complaining that GENAPIC_EXPORTS is undefined... How to get around that?
I am attaching PylonC.h file which I think is enough to help me. The rest of the whole api is available on basler's website: http://www.baslerweb.com/MV_Customer_Service_Downl​oads_pylon-Linux-Text-16855.html. I am using Pylon 3.0 64-bit , C version.
Attachments:
PylonC.h ‏33 KB

Answer 1

you forgot to add the genapi include directory path in the second step. Your include file references this here:
#include <genapic/GenApiC.h>
And don't try to generate wrappers for DLLRegisterServer and DLLUnregisterServer.
And last but not least, don't expect the Import Library Wizard to create magic. It can create the DLL caller VIs for you but it can not guess at how this API should be used. A C header file only gives information about how to link to the function, but none at all about how to use it. A LabVIEW VI usually also implements quite a bit about how the API is used (preparing parameters such as preallocating output buffers, etc) that is really impossible to deduce from the header file alone. It's what a C programmer continously has to worry about when calling functions and since you are incorperating this API into LabVIEW you have to worry about it too. Otherwise it will just cause exceptions.
So you will have to go through every and each VI and check it for such problems, which is really the hard work. Creating the VIs that call the functions with Call Library Nodes may seem like a lot of work, but once you have done one or two it's absolutely trivial in comparison to the real hard work that the Import Library Wizard can't do for you at all.
Rolf Kalbermatter
CIT Engineering Netherlands
a division of Test & Measurement Solutions