Experimental Physics and
Industrial Control System

"J. Frederick Bartlett ([email protected])" <[email protected]> · Wed, 01 Dec 1999 15:52:00 CST

Jeff,

  Yes, DEC threads is a real thread-supporting package with a rich
assortment of synchronization mechanisms. The early version of this,
which is probably what your documentation describes, was a prototype
for what became POSIX threads (POSIX.4A) or pthreads. Unfortunately,
The DEC threads package was superior, in many ways, to pthreads. Your
document should also describe the early version of pthreads as well.

  Most platforms provide an implementation of pthreads and that,
probably, is the best choice of a threading package if you want
maximum portability. Depending upon the implementation, the threads
may not be known to the OS (user-space), known to the OS kernel
(kernel-space), or somewhere in between. One of the deficiencies of
pthreads is that it does not offer a recursive mutex; so, if the same
thread tries to lock a mutex more than once, as might occur when
library packages are used, the thread becomes permanently blocked. It
is possible, however, to create a recursive lock using the pthreads
routines.

  An alternative to pthreads is ACE that, although it is principally a
high-level message-passing package, has thread support included.  It
works on many platforms although the installation is not trivial and
the size is daunting.  It is probably possible to remove the thread
support and use it without all of the other, memory overhead. As I
recall, ACE uses pthreads on many of the supported platforms.

  For an introduction to the topic, you might start with one of the
O'Reilly & Associates books, "Pthreads Programming", by Nichols,
Buttlar, and Farrell. A superior book is "Programming with Threads" by
Kleiman, Shah, and Smaalders published by Prentice-Hall.

						Fritz

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System