WindowsPromoteStringBuffer function (winstring.h)

Creates an HSTRING from the specified HSTRING_BUFFER.

Syntax

HRESULT WindowsPromoteStringBuffer(
 HSTRING_BUFFER bufferHandle,
 HSTRING *string
);

Parameters

bufferHandle

Type: [in] HSTRING_BUFFER

The buffer to use for the new HSTRING. You must use the WindowsPreallocateStringBuffer function to create the HSTRING_BUFFER.

string

Type: [out] HSTRING*

The newly created HSTRING that contains the contents of bufferHandle.

Return value

Type: HRESULT

This function can return one of these values.

Remarks

Use the WindowsPromoteStringBuffer function to create a new HSTRING from an HSTRING_BUFFER. Calling the WindowsPromoteStringBuffer function converts the mutable buffer to an immutable HSTRING. Use the WindowsPreallocateStringBuffer function to create the HSTRING_BUFFER.

If the WindowsPromoteStringBuffer call fails, you can call the WindowsDeleteStringBuffer function to discard the mutable buffer.

Each call to the WindowsPromoteStringBuffer function must be matched with a corresponding call to WindowsDeleteString.

Examples

The following code example demonstrates how to use the WindowsPromoteStringBuffer function.

#include <winstring.h>

int main()
{
 HSTRING hString = NULL;
 HSTRING_BUFFER hStringBuffer = NULL;
 PWSTR strBuffer = NULL;

 HRESULT hr = WindowsPreallocateStringBuffer(10, &strBuffer, &hStringBuffer);

 if (SUCCEEDED(hr))
 {
 // Fill in the buffer

 hr = WindowsPromoteStringBuffer(hStringBuffer, &hString);

 if (SUCCEEDED(hr))
 {
 WindowsDeleteString(hString);
 }
 else
 {
 WindowsDeleteStringBuffer(hStringBuffer);
 }
 }
}

Requirements

See also

HSTRING

HSTRING_BUFFER

WindowsDeleteString

WindowsDeleteStringBuffer

WindowsPreallocateStringBuffer