Implementation of a buffer release strategy.

* Tests for Release feature.
* Check vector_downward.buf_ before passing to deallocator.
* Assertions.
* Shared test between unique_ptr and GetBufferPointer()
* Unnecessary using directives.
* Reallocate vector if released on clear operation.
* Use allocator attribute.
* Renamed `Release()` to `ReleaseBufferPointer()`
* For consistency with `GetBufferPointer()`
* Updated documentation for ReleaseBuffer.

Change-Id: I108527778e56ae5127abf9e5b1be6b445ad75cb7

1 files changed, 6 insertions, 0 deletions

diff --git a/docs/source/CppUsage.md b/docs/source/CppUsage.md
index 3bd70697..ef7272ac 100755
--- a/docs/source/CppUsage.md
+++ b/docs/source/CppUsage.md
@@ -112,6 +112,12 @@ be compressed, or whatever you'd like to do with it. You can access the
 start of the buffer with `fbb.GetBufferPointer()`, and it's size from
 `fbb.GetSize()`.
 
+Calling code may take ownership of the buffer with `fbb.ReleaseBufferPointer()`.
+Should you do it, the `FlatBufferBuilder` will be in an invalid state,
+and *must* be cleared before it can be used again.
+However, it also means you are able to destroy the builder while keeping
+the buffer in your application.
+
 `samples/sample_binary.cpp` is a complete code sample similar to
 the code above, that also includes the reading code below.