Add C++ notes

_posts/2025-01-16-19.0.0-release.md

@@ -52,37 +52,50 @@ TODO
 
 ## C++ notes
 
-TODO
-
-### Acero
-
-TODO
-
 ### Compute
 
-TODO
+It is now possible to cast from a struct type to another struct type with
+additional columns, provided the additional columns are nullable (GH-44555).
 
-### Dataset
+The compute function `expm1` has been added to compute `exp(x) - 1` with better
+accuracy when the input value is close to 0 (GH-44903).
 
+Hyperbolic trigonometric functions and their reciprocals have also been added
+(GH-44952).
 
 ### Filesystems
 
-TODO
+The S3 filesystem has gained support for server-side encryption with customer
+provided keys, aka SSE-C (GH-43535).
 
-### Gandiva
+The S3 filesystem also gained an option to disable the SIGPIPE signals that may
+be emitted on some network events (GH-44695).
 
-TODO
+The Azure filesystem now supports SAS token authentication (GH-44308).
 
-### GPU
+### Flight RPC
 
+The UCX backend has been deprecated and is scheduled for removal (GH-45079).
 
-### IPC
+### Memory management
 
-TODO
+Mimalloc is now the default allocator, while jemalloc is disabled by default
+due to reports of compatibility issues on various platforms (GH-44976). While
+we do not expect this to cause any functional regression, it may lead to different
+memory consumption and performance characteristics depending on memory-intensive
+workloads.
 
 ### Parquet
 
-TODO
+The initial footer read size can now be configured to reduce the number of
+potential roundtrips on high-latency filesystems such as S3 (GH-45015).
+
+The new SizeStatistics format feature has been implemented, though it is
+disabled by default when writing (GH-40592).
+
+### Miscellaneous
+
+`ChunkResolver` is now exposed as a public API (GH-34535).
 
 ## C# notes
 
@@ -134,4 +147,4 @@ TODO
 [4]: {{ site.baseurl }}/docs/r/news/
 [5]: https://github.com/apache/arrow-rs/tags
 [6]: https://github.com/apache/arrow-go/tags
-[7]: https://github.com/apache/arrow-java/tags
+[7]: https://github.com/apache/arrow-java/tags