CS::SkipList Library is a C++ template library of containers based on skip lists. These containers work like sets and maps, but can also be accessed via numerical index. This collection has vector-like containers where all operations work in logarithmic time. It also has a composite container where you can order the same elements in many different ways at the same time.
QtWebSockets is a pure Qt implementation of WebSockets, both client and server. It is implemented as a Qt source code module (.pri file) that can easily be embedded into existing Qt projects. It has no dependencies other than Qt. It features text and binary sockets, frame-based and message-based signals, proxy support, and strict Unicode checking.
The STX ExecPipe library provides a convenient C++ interface to execute child programs connected via pipes. It is a front-end to the system calls fork(), pipe(), select(), and execv() and hides all the complexity of these low-level functions. It allows a program to build a sequence of connected children programs with the input and output of the pipe sequence redirected to a file, string, or file descriptor. The library also allows custom asynchronous data processing classes to be inserted into the pipe or placed at the source or sink of the sequence.