| ### What is DCE Threads? DCE Threads is a user-level (nonkernel) threads library based on the pthreads interface specified by POSIX in their 1003.4a standard (Draft 4). It consists of an API that gives programmers the ability to create and manipulate threads, as described in Programming with DCE Threads. The other technology components of OSF's Distributed Computing Environment assume the availability of threads support. DCE Threads is provided for use on operating systems that do not provide threads already; if a threads package is already available, then DCE Threads may not be needed. DCE Threads can be used as is - as a user-level threading facility - or it can be mapped to an existing threads facility provided by the host operating system. DCE Threads is designed for compatibility with existing operating systems that deal with processes rather than threads, and libraries that are not reentrant (that is, not written to handle multiple threads executing within them at the same time). This compatibility is provided through the use of jacket routines, which are used in conjunction with existing libraries, and modified operating system calls. Since messages from the outside world (such as interrupts and signals) have traditionally been addressed to a process, rather than a specific thread in a process, this interaction must be modified as well. For further information on the way DCE Threads interacts with other software, see the topics on threads in the OSF DCE Application Development Guide. ###