This topic examines UNIX signals in relationship to the D3 virtual machine.
The discussion is intended for experienced UNIX programmers to interface UNIX applications with D3 or to use UNIX process synchronization in a purely D3 environment.
For performance reasons, UNIX signals are not used in regular D3 activity. They are used solely to handle exceptions. Diverting signal usage for an application would remove nonessential facilities, such as sending messages or logging off a process. This does not mean that signals can be used freely, though. The D3 monitor provides a system call to process regular D3 signals inside a customized signal handler, thus combining system and application signal handling.