BSTR class
A string data type that is commonly used by OLE Automation, as well as some COM methods.
BSTR types differ from Pointer<Utf16> in that they include a four byte
prefix stored immediately prior to the string itself that represents its
length in bytes. The pointer points to the first character of the data
string, not to the length prefix.
BSTRs should never be created using Dart's memory allocation functions.
For instance, the following code is incorrect, since it does not allocate
and store the length prefix.
final bstr = 'I am a happy BSTR'.toNativeUtf16();
This class wraps the COM memory allocation functions so that BSTR types
can be created without concern. Instead of the above code, you can write:
final bstr = BSTR.fromString('I am a happy BSTR');
A debugger that examines the four bytes prior to this location will see a 32-bit int containing the value 34, representing the length of the string in Utf-16.
Dart does not garbage collect BSTR objects; instead, you are responsible
for freeing the memory allocated for a BSTR when it is no longer used. To
release its memory, you can call an object's free method.
Constructors
- BSTR.fromString(String str)
-
Create a BSTR from a given Dart string.
factory
Properties
- byteLength → int
-
Returns the length in bytes.
no setter
- hashCode → int
-
The hash code for this object.
no setterinherited
- length → int
-
Returns the length in characters.
no setter
-
ptr
→ Pointer<
Utf16> -
A pointer to the start of the string itself.
final
- runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
Methods
-
clone(
) → BSTR - Allocates a new string that is a copy of the existing string.
-
free(
) → void - Releases the native memory allocated to the BSTR.
-
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent method or property is accessed.
inherited
-
toString(
) → String -
Returns the contents of the BSTR as a regular Dart string.
override
Operators
-
operator +(
BSTR other) → BSTR - Concatenate two BSTR objects and returns a newly-allocated object with the results.
-
operator ==(
Object other) → bool -
The equality operator.
inherited