Passing an array of strings from VB to C
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From: Francogrex on 23 Jan 2010 10:33 Hi, I can pass single strings between VB and C (dll) without problem. But now I am trying to pass an array of strings from VB to a C file (as a test) but that is not working at all maybe someone can give hints. I'm using VBA for excel. Thanks. The C file that is made into 'mydll.dll" #include "windows.h" #include "string.h" #include "stdio.h" #include "stdlib.h" __declspec (dllexport) void __stdcall CFUN(LPSTR **pout) { FILE *in=fopen("c:/excel.txt","w"); int i; for (i=0;i<4;i++) { fprintf(in, "%s\n", *(pout+i)); } fclose(in); } The VBA code: Private Declare Function CFUN& Lib "c:/mydll.dll" (ByRef pout As String) Sub TEST() Dim pout(4) As String pout(0) = "one" pout(1) = "two" pout(2) = "three" pout(3) = "four" CFUN (pout(0)) End Sub The excel.txt file does not contains the strings.
From: Ralph on 23 Jan 2010 10:54 Francogrex wrote: > Hi, I can pass single strings between VB and C (dll) without problem. > But now I am trying to pass an array of strings from VB to a C file > (as a test) but that is not working at all maybe someone can give > hints. I'm using VBA for excel. Thanks. > "How To Pass Arrays Between Visual Basic and C" http://support.microsoft.com/kb/207931 An 'Array' is an object in VB. In C it is a block of memory using an addressing convention. You can manage VB Arrays in C using a SAFEARRAY, but VB also provides methods to manage the "array buffer" as a contiguous block. -ralph
From: MikeD on 23 Jan 2010 11:10 "Francogrex" <franco(a)grex.org> wrote in message news:8b12cee0-2a0e-4c6f-b452-17cb35b0b738(a)a32g2000yqm.googlegroups.com... > Hi, I can pass single strings between VB and C (dll) without problem. > But now I am trying to pass an array of strings from VB to a C file > (as a test) but that is not working at all maybe someone can give > hints. I'm using VBA for excel. Thanks. You can try what's in these KB articles, but note that they are for VB, not VBA. There could be differences, or the information could be completely inapplicable to VBA. That's why there are separate newsgroups for VBA. How to pass arrays and strings between Visual Basic and C functions or between Visual Basic and C++ functions by using Visual Basic 6.0 http://support.microsoft.com/kb/205277 How To Pass a String Between Visual Basic and Your C DLL http://support.microsoft.com/kb/187912 How To Pass Array of UDTs with Variable Length Strings to C/C++ http://support.microsoft.com/kb/194609 If these don't help, I suggest you ask in a VBA newsgroup. -- Mike
From: Francogrex on 23 Jan 2010 13:28 On Jan 23, 5:10 pm, "MikeD" <nob...(a)nowhere.edu> wrote: > If these don't help, I suggest you ask in a VBA newsgroup. Ok I did, I'm sorry, I had asked many times VBA questions in excel/ programming forums but I rarely get replies and I don't think the level of expertise in programming in those forums is as high as here.
From: Ralph on 23 Jan 2010 14:54
Francogrex wrote: > On Jan 23, 5:10 pm, "MikeD" <nob...(a)nowhere.edu> wrote: >> If these don't help, I suggest you ask in a VBA newsgroup. > > Ok I did, I'm sorry, I had asked many times VBA questions in excel/ > programming forums but I rarely get replies and I don't think the > level of expertise in programming in those forums is as high as here. The 'coding' aspects in *this* case are identical. Starting with VBA 5.x and VB 5 the 'core' language of both platforms is identical. The difference between the two is primarily the language 'extension libraries' availble to a specific host environment and the fact VBA applications/macros etc. can only be run within a host. Becoming an advanced programmer in VBA entails learning the difference as well as learning the nuances of the extension libraries for a specific product. An excellent reference book on the core language of both VBA and VB is O'Reilly's "VB & VBA In A Nutshell" by Paul Lomax. It is out of print, but used books can be purchased on the web for practically the cost of shipping. -ralph |