If you already know what those features are, please feel free to skip this section. Many programming guides skim briefly over the security-relevant portions of Linux or Unix and skip important information. Conversely, there's a great deal of detailed information in the manual pages about individual functions, but the manual pages sometimes obscure key security issues with detailed discussions on how to use each individual function. This section has more depth than the typical programming guides, focusing specifically on security-related matters, and points to references where you can get more details. First, the basics.
Processes can also set signals.
The next few subsections detail this. When programming a multi-threaded application, it's usually better to use one of the standard thread libraries that hide these differences. Not all Unix-like systems support this. This is a Linux-unique attribute. This book is not a full tutorial on writing programs, so I will skip widely-available information handling processes.