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Facebook's branch of Apache Thrift, including a new C++ server.
Causal Dynamical Triangulations in C++ using CGAL
GZDoom adds an OpenGL renderer to the ZDoom source port.
A proof-of-work blockchain system based on a novel consensus mechanism design based on a Structured DAG.
Xournal++ is a handwriting notetaking software with PDF annotation support. Written in C++ with GTK3, supporting Linux (e.g. Ubuntu, Debian, Arch, SUSE), macOS and Windows 10. Supports pen input from devices such as Wacom Tablets.
Bitcoin Cross-Platform C++ Development Toolkit
A C++, header-only library for constructing JSON and JSON-like data formats, with JSON Pointer, JSON Patch, JSONPath, CSV, MessagePack, CBOR, BSON, UBJSON
Pony is an open-source, actor-model, capabilities-secure, high performance programming language