.TH MPD 1 "3 Nov 2000" "University of Arizona"
.SH NAME
mpd \- MPD compiler
.SH SYNOPSIS
\fBmpd [\|\-sbcqwegvOTMCFP\|]
[\|\-I \fRdir\fB\|]
[\|\-o \fRfile\fB\|]
[\|\-d \fRflags\fB\|]
\fRfile.mpd ... otherfiles...
.br
.SH DESCRIPTION
.LP
.I Mpd
compiles programs written in the MPD language.
In the usual case, one or more
.B .mpd
files are compiled to produce
.B .o
files, and then the MPD linker,
.IR mpdl (1),
is called to produce an executable file
.BR a.out .
The last encountered resource is taken as the main resource.
.LP
Compilation and linking takes place in the context of an
.I MPDinter
directory used for passing specification and object files between
.I mpd
and
.I mpdl
runs.
Files are created in the MPDinter directory
as each resource or global is compiled.
The MPDinter directory is needed for compilation and linking,
but not execution, and can be deleted after an executable has been produced.
.LP
Each source file is read twice.
The first pass copies component specifications into the MPDinter directory;
the second pass generates object code.  
If errors are detected in the first pass, the second pass is omitted.
.LP
Files not ending in \fB.mpd\fP
(such as \fB.o\fP, \fB.a\fP, and \fP\-l\fP\fIxx\fP files)
are not processed by
.I mpd
but are passed along to
.IR mpdl .
.SH OPTIONS
.LP
Any of the options
.BR s , 
.BR b , 
.BR c , 
.BR M , 
or 
.BR C
inhibits linking.
.TP
.BI \-I " dir"
Use
.IR dir /MPDinter
as the MPDinter directory instead of ./MPDinter.
.TP
.BI \-o " file"
Use
.I file
for the executable instead of
.BR a.out .
.TP
.B \-s
Create specification files only (first pass only).
.TP
.B \-b
Compile bodies only (second pass only), leaving specification files unaltered.
.TP
.B \-c
Compile specs and bodies, but do not link
.B .o
files to create an executable file.
.TP
.B \-q
Suppress the echoing of source file names as they are compiled.
.TP
.B \-w
Suppress warning messages.
.TP
.B \-O
Omit some runtime error checks and
invoke the C optimizer to improve the generated code.
.TP
.B \-T
Omit the ``timeslicing'' code that allows context switching at the top
of each loop.
.TP
.B \-M
Generate dependency information for use by
.IR mpdm (1),
then exit without compiling anything.
.LP
Additional options are useful mainly when debugging the compiler:
.TP
.B \-C
Stop after generating
.B .c
files, leaving them undeleted.
.TP
.B \-F
Inhibit constant folding.
This can break programs by rendering certain expressions non-constant.
.TP
.B \-P
Inhibit normal optimizations in the MPD compiler.
.TP
.BI \-d " flags"
Write debugging output selected by
.I flags
on standard output.
.TP
.B \-e
Use experimental versions of
.I mpdl
and
.B .h
files,
and pass
.B \-e
to
.I mpdl.
.TP
.B \-g
Compile for debugging with
.IR dbx (1),
don't delete
.B .c
files, and pass
.B \-g
to
.I mpdl.
.TP
.B \-v
Announce version number,
trace other programs invoked by
.IR mpd ,
and pass
.B \-v
to
.IR mpdl .
.SH ENVIRONMENT
.IP MPD_PATH
When compiling an
.B import
statement,
.I mpd
searches for a corresponding
.B .spec
file by looking first in the current directory,
then in the MPDinter directory,
and finally in the MPD library.
If MPD_PATH is set, any directories named there are checked
ahead of the standard search sequence.
Directories in MPD_PATH are separated by colons (\fB:\fP).
.br
.ne 8
.SH "EXECUTION ENVIRONMENT"
.LP
These environment variables can be set at execution time to affect
the behavior of an MPD program:
.IP MPD_PARALLEL
Controls the number of processes that can run with true concurrency
(as opposed to simulated concurrency) under MultiMPD.
MultiMPD is a configuration option available on
the SGI Iris, Sun Sparc running Solaris 2.x, and Sequent Symmetry.  
The default value is 1 (no true concurrency).
It makes little sense to set MPD_PARALLEL greater than the number
of available processors.
.IP MPD_SPIN_COUNT
In MultiMPD, the number of times an idle processor will check for a task
before relinquishing the CPU to the operating system.
Larger values increase the opportunity for processes to quickly resynchronize
at the expense of greater CPU usage.
The default is 35.
.IP MPD_NAP_INTERVAL
In MultiMPD, the number of milliseconds an idle processor will nap
after trying unsuccessfully to find something to run.
The default is 10.
.IP MPD_TRACE
If not null, MPD_TRACE specifies the name of a file to receive a trace
of messages, invocations, and other language-level events.
Two special names, 
.I stdout
and
.I stderr,
direct the trace output to standard output and standard
error output respectively.
The default is no tracing.
Traces from remote virtual machines appear only if the trace is
directed to
.I stdout
or 
.I stderr.
The
.IR mpdprof (1)
program can be used to summarize the trace output.
.IP MPD_DEBUG
A hexadecimal number specifying a bit mask that enables debugging 
information of various internal runtime events on standard error 
output.  Each bit selects a different message category, and the 
higher order bits (FFFFFF00) produce the most voluminous output.  
Details are contained in the source code of the runtime system.  
The default is no debugging.
In contrast with MPD_TRACE, the output from MPD_DEBUG records
internal events of interest to maintainers of the runtime system.
.IP MPDXPATH
Path to the executable of
.IR mpdx ,
which serves as the central controller of a distributed MPD program.
The default is configured when the MPD system is built.
.IP MPDMAP
File to read for the network configuration information used to generate
a host-independent ``network path'' of the executable
for executing part of an MPD program on a remote host.
The default is configured when the MPD system is built.
.SH FILES
.ta 27n
file.mpd	MPD source file
.br
a.out	executable program
.br
MPDinter/component.c	C language intermediate file
.br
MPDinter/component.spec	specification file
.br
MPDinter/global.impl	global characteristics
.br
MPDinter/component.o	object file
.SH SEE ALSO
Gregory R. Andrews,
.I "Foundations of Multithreaded, Parallel, and Distributed Programming."
Addison\-Wesley, 2000, ISBN 0\-201\-35752\-6.
.LP
mpdl(1), mpdm(1), mpdprof(1), cc(1), dbx(1), mpdmap(5), mpdtrace(5)
.LP
The MPD web page, http://www.cs.arizona.edu/mpd/.
.SH DIAGNOSTICS
.LP
Messages diagnosing erroneous programs are intended to be self-explanatory.
.LP
Messages indicating ``compiler malfunction'',
or any error messages generated by the C compiler,
indicate bugs in the MPD compiler
that should be reported to its implementors.