Re: passing char * to dll

From:
Norbert Unterberg <nunterberg@newsgroups.nospam>
Newsgroups:
microsoft.public.vc.mfc
Date:
Sat, 08 Mar 2008 11:43:34 +0100
Message-ID:
<#J1fGlQgIHA.3352@TK2MSFTNGP04.phx.gbl>
Rami schrieb:

Hi all,
I call an exported function from the main program as follows
   print_in_LogFile("Specific_Message_Circular_Buffer_Index", 0);
The exported function inside the dll follows
////////////////////////////////////////////////////////////////////////////////////////////////////
_declspec(dllexport)print_in_LogFile(char * text,int g_nconnection )

===================
Several issues here:

* If you do not plan to modify "test", you should pass a const pointer. Using a
char* and passing it a string literal "Specific_Message_Circular_Buffer_Index"
only works because the C++ compiler supports this special case for compatibility
with old C code.

* In modern windows applications, using "char" as a type is basically obsolete,
except for some special cases. The world is shiftin to uinicode, so you should
either use TCHAR or WCHAR/wchar_t instead.

* The variable name prefix g_ is commonly used for global variables. A functino
argument is not global. So either the g_ does not belong here, or your naming
connention is somehow unconventional.
===================

{
 AFX_MANAGE_STATE(AfxGetStaticModuleState());
 if (text == "Specific_Message_Circular_Buffer_Index")

==================
Are you comming from the C# or Java world?

Comparing char pointers strings with "==" does compare the strings in C/C++, it
compares the pointers. To compare the strings, you need some string comparing
functions like strcmp, stricmp or CompareString, whatever is more appropriate to
your application.
==================

 {
   // Do something
    .....
}
problem is that the comparison with the "if" gets a FALSE value though with
a debugger I can see taht it should be TRUE.

Can someone advise please?


Norbert

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