# V1060\. Passing 'BSTR ' to the 'SysAllocString' function may lead to incorrect object creation\.

The analyzer has detected the passing of a string of type 'BSTR' to the 'SysAllocString' function\.

```cpp
BSTR FirstBstr = ....;
BSTR SecondBstr = SysAllocString(FirstBstr);
```

Copying a 'BSTR' string by passing it to the 'SysAllocString' function may result in a logic error\.

BSTR \(basic string or binary string\) is a string data type that is used by COM, Automation, and Interop functions\. BSTR is represented in the following way:

1. **Length prefix**\. A four\-byte integer that contains the number of bytes in the following data string\. It appears immediately before the first character of the data string and does not include the terminator\.
1. **Data string**\. A string of Unicode characters\. May contain multiple embedded null characters\.
1. **Terminator**\. Two null characters\.

A BSTR is a pointer that points to the first character of the string, not to the length prefix\.

The 'SysAllocString' function handles 'BSTR' strings in the same way as it does regular wide C strings\. It means that if the string contains multiple embedded null characters, 'SysAllocString' will return a truncated string\. To avoid unexpected behavior, rewrite the code using wrapper classes over 'BSTR' such as 'CComBSTR' or '\_bstr\_t'\. 

For example, you can use the following pattern to correctly copy one 'BSTR' string to another:

```cpp
CComBstr firstBstr(L"I am a happy BSTR.");
BSTR secoundBstr = firstBstr.Copy();
```

This is another way to do it:

```cpp
_bstr_t firstBstr(L"I am a happy BSTR too.");
BSTR secoundBstr = firstBstr.copy();
```