A problem with BSTR

[nabil035]

this is my code:

BSTR A;

//I put data in A and I test it through a message box and all things are alright

MyFunction(A);


//I have an error in my function

when I write this code:

USES_CONVERSION;
OLECHAR desc[23];
char A[23]="mydata";
int i;
for (i=0;i<23;i++)
{
desc[i]=(OLECHAR)A[i];
}
MyFunction(desc)
//the function succeeds

I want to know why the first code doesn't run correctly
this problem frustrate me cuz I know that the use of (OLECHAR*) and (OLECHAR[23]) are similar!!!!!
and the most surprising thing for me than even this dont work

A=desc
MyFunction(A);

please help or give me any idea!!!!

[weaknessforcats]

An OLECHAR is a 16-bit Unicode character. Your message box needs an 8-bit character. The typecase does nothing except tells the compiler to forget that the assignment won't work.

The fundamental error here is in not using TCHAR instead of char. That would mena using all of the TCHAR mappings. You can check MSDN for this.

You cannot reliable mix ASCII and UNICODE in the same Windows program.

[nabil035]

well, thx I understand but not a lot


u mean that BSTR which is an OLECHAR*

and OLECHAR array don't use the same type of coding!!!

[weaknessforcats]

That is correct. An OLECHAR is a typedef for a char and a BSTR is a typedef of an OLECHAR*.

But- a BSTR is a data structure that has a different format than a plain old OLCHAR string.

You have to use the COM Automation string manipulation functions to get a BTSR from a string of OLECHAR.

Read this: http://msdn2.microsoft.com/en-us/lib...05(VS.85).aspx.

[nabil035]

Thx now I resole my problem

it was a problem in my function


I have now a good idea about BSTR

thx