diff options
1 files changed, 9 insertions, 0 deletions
diff --git a/doc/posix1003.1/preface.texi b/doc/posix1003.1/preface.texi
index f14a9b58a6..562c7e58d6 100644
--- a/doc/posix1003.1/preface.texi
+++ b/doc/posix1003.1/preface.texi
@@ -18,3 +18,12 @@ this document corresponds to a section in the 1003.1 standard
and the implementation status of the items required by the standard
are listed.
+RTEMS supports a number of POSIX process, user, and group oriented
+routines in what is referred to as a "SUSP" (Single-User, Single
+Process) manner. RTEMS supports a single process, multithreaded
+POSIX 1003.1b environment. In a pure world, there would be
+no reason to even include routines like @code{getpid()} when there
+can only be one process. But providing routines like @code{getpid()}
+and making them work in a sensible fashion for an embedded environment
+while not returning ENOSYS (for not implemented) makes it significantly
+easier to port code from a UNIX environment without modifying it.