BSTR / LPCSTR question

hello,

  I am expermenting with writing COM components using ATL COM wizard. Now I have one user defined function in my ActiveX Server component.

STDMETHODIMP Cdeers::fnDeersdll(BSTR argv, BSTR *returned_record)

Now, I would like to use Strlen function call on "argv" parameter in my function, but it won't allow me. I need to convert it into a regular string so that I use associated string function calls. Similarly, I need to convert a "LPCSTR" type to "BSTR *", how do I do it? Thanks.
dbdoshiAsked:
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jkrConnect With a Mentor Commented:
Well, your question was: "I need to convert a "LPCSTR" type to "BSTR *"

But, for the other way round, use

_bstr_t::operator char*( ) const;

(as LPCSTR _is_ a char*), e.g.

LPCSTR _p1 ="abcdef";
_bstr_t _b ( _p);

BSTR bstr = _b.copy();

LPCSTR _p2 = (char*) _b;

If you have a BSTR*, you'll have to

BSTR* pb;

// ...

_bstr_t _b2 ( *pb);

LPCSTR _p2 = (char*) _b2;






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jkrCommented:
>>I need to convert a "LPCSTR" type to "BSTR *", how do I do it?

Use '_bstr_t':

#include <comdef.h>

LPCSTR _p ="abcdef";
_bstr_t _b ( _p);

BSTR bstr = _b.copy();
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dbdoshiAuthor Commented:
How do I convert a BSTR to LPCSTR?
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Meir RivkinFull stack Software EngineerCommented:
use _bstr_t:

example:

#include <comdef.h>
     LPCSTR lpcstr = "Jonny";
     _bstr_t b(lpcstr);
     

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Meir RivkinFull stack Software EngineerCommented:
using char*()

example:

LPCSTR lpcstr = "Jonny";
    _bstr_t b(lpcstr);

LPCSTR str = (char*)b;
   


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Meir RivkinFull stack Software EngineerCommented:
jkr, u r much quicker than me :)
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kuchnaheenCommented:
u ppl r so cool...i am just starting ATL/COM..
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jkrCommented:
Well, anything else you need to know?
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dbdoshiAuthor Commented:
Just one more thing...(though its unrelated to my original question). As I had explained earlier, my user defined function in my ActiveX server object is:

STDMETHODIMP Cdeers::fnDeersdll(BSTR argv, BSTR *returned_record)

Here, the "argv" variable is my [in] variable, which I pass to my function. The function does some socket connections, and makes a string which I pass return back, called "[out, retval] returned record". Now the above function "fnDeersdll" returns a "HRESULT" type, as far as I understand.

Now I have this sample code in my function.

ret = send(client_socket, encrypt_inquiry, remainder, 0);
if(ret == SOCKET_ERROR)
     {
          closesocket(client_socket);
          WSACleanup();
          return -1;
     }

Finally, if all code executes properly, I say "return 0" as the end of the function.

Now, I need to test this "0" or "1" in my calling script (my ASP Page which is going to use this component), how do I go about doing that? I cannot tack the "0/1" to my returned_record variable. Is there any other "out" variable that I need to define?





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jkrCommented:
In ASP, you can use the 'Number' property of your 'Err' object - see http://msdn.microsoft.com/library/default.asp?url=/library/en-us/comsrv2k/htm/cs_rp_comparammem_isay.asp

Quote:

"Standard COM Errors
Many, but not all, of the properties and methods of the Commerce Server objects use standard Component Object Model (COM) HRESULT return values to communicate whether the operation was successful or not.

In C++, these values are the actual return values from the methods themselves (including property get_ and put_ methods). The program must explicitly perform error checking by examining these return values, or use some variation of structured error handling.

In Microsoft Visual Basic (VB), and in Visual Basic Scripting Edition (VBS) as used in Active Server Pages (ASP), these values are placed in the Number property of the global Err object."
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