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Marshal.FreeBSTR

This tag is associated with 4 posts

Passing Managed Structures With Strings To Unmanaged Code Part 3

1. Introduction. 1.1 In part 1 of this series of blogs we studied how to pass a managed structure (which contains strings) to unmanaged code. The structure was passed as an “in” (by-value) parameter, i.e. the structure was passed to the unmanaged code as a read-only parameter. 1.2 Then in part 2, we studied the techniques for receiving … Continue reading

Passing Managed Structures With Strings To Unmanaged Code Part 2

1. Introduction. 1.1 In part 1 of this series of blogs we studied how to pass a managed structure (which contains strings) to unmanaged code. The structure was passed as an “in” (by-value) parameter, i.e. the structure was passed to the unmanaged code as a read-only parameter. 1.2 Here in part 2, we shall explore the … Continue reading

Using BSTR in Managed Code Part 1

1. Introduction. 1.1 The COM BSTR may be used within managed code for various purposes including the exchanging of strings to and from unmanaged code. 1.2 There are several ways to work with BSTRs and these are listed in summary below : Using Marshal Class methods (e.g. Marshal.PtrToStringBSTR(), Marshal.StringToBSTR(), Marshal.FreeBSTR()). Using Unmanaged APIs (e.g. SysAllocString(), SysFreeString(), etc). … Continue reading

Returning Strings from a C++ API to C#

1. Introduction. 1.1 APIs that return strings are very common. However, the internal nature of such APIs, as well as the use of such APIs in managed code, require special attention. This blog will demonstrate both concerns. 1.2 I will present several techniques for returning an unmanaged string to managed code. But before that I shall first provide an … Continue reading