m_kill_procs() and streams

[Jim Riordan]

    I have been trying to use the multiprocessing library in IRIX
Release 3.2 but I am having trouble with m_kill_procs() interfering
with streams.  I have included a shar file demonstrating the problem.

    The program reads a stream and then does one a a few things
according to the input.  When I choose an option which uses the
multiprocessing, characters on the stream after that option seem to
get flushed.  The 'h' routine does not use multiprocessing while the
'a' routine does. If I type "h h", then the 'h' routine gets called
twice.  If I type "h a a some_more_sufff", the 'h' routine gets
executed, the 'a' routine gets called once and the program returns
never having read the rest of the input.  If the current stream is
stdin, I can then continue. Streams other than stdin or pipes yield
similiar results.

    If the answer is obvious, please responed/flame by email.

Thanks in advance,

-james

+---------------+-----------------------+------------------------------+
| James Riordan | This space left blank | james at smectos.gang.umass.edu |
+---------------+-----------------------+------------------------------+

x---x----x----x----x----x----x-CUT  HERE-x----x----x----x----x----x----x
#! /bin/sh
# This is a shell archive. Kill anything before the /bin/sh line, then unpack
# it by saving it into a file and typing sh file. To overwrite existing
# files, type sh file -c.
# Contents: problem
# Wrapped by james at diogenes on Mon Jul 9 19:51:15 EDT 1990
PATH=/bin:/usr/bin:/usr/ucb;export PATH
echo shar: making directory problem
mkdir problem
if test -f 'problem/ptest.c' -a "${1}" != "-c"; then
echo shar: Will not clobber existing file \"'problem/ptest.c'\"
else
echo shar: Extracting \"'problem/ptest.c'\" \( 1736 characters \)
sed "s/^X//" > 'problem/ptest.c' << 'THE-END-OF:problem/ptest.c'
X#include <stdio.h>
X#include <ulocks.h>
X#include <errno.h>
X
X#ifndef NPROCS
X#define NPROCS 4
X#endif /* NPROCS */
X
X
Xvoid foo_bar()
X{
X  int count;
X  double foo = 0.0;
X
X  fprintf (stderr, ".");
X
X#ifdef WATCH_GR_OSVIEW  /* waste some parallel processor time */
X  for (count = 0; count < 100000; count++) foo = (foo + foo)/2.0;
X#endif /* WATCH_GR_OSVIEW */
X}
X
X
Xvoid par_apply_fun (void (*func)())
X{
X  unsigned int count;
X
X  for (count = m_get_myid(); count < 64; count += NPROCS) {
X    func();
X  };
X
X  m_sync();
X}
X
Xvoid p_apply_fun (void ((*func)()))
X{
X  m_set_procs (NPROCS);
X
X  if (m_fork (par_apply_fun, func)) {
X    perror ("\nm_fork\n");
X  };
X
X  if (m_kill_procs ()) {
X    perror ("\nm_kill_procs: ");
X  };
X}
X
Xint main(int argc, char **argv)
X{
X  FILE *command = stdin;
X  char action;
X
X  if (argc == 2) {
X    command = fopen (argv[1], "r");
X    if (!command) {
X      fprintf ("Unable to open %s. Reverting to stding.\n", argv[1]);
X      command = stdin;
X    };
X  };
X    
X  fprintf (stdout, "test: ");
X
X  while ((action != 'q')&&!feof(command)) {	/* main event loop */
X
X    fscanf (command, "%c", &action);
X    switch (action) {
X
X    case 'a':
X      p_apply_fun (foo_bar);
X      fprintf (stdout, "\nDone.\ntest: ");
X      break;
X
X    case 'h':
X      fprintf (stdout, "This is a test.\n");
X      break;
X
X    case '?':
X      fprintf (stdout, "a\tFork and kill some useless process\n");
X      fprintf (stdout, "h\tPrint a meaningless meassage.\n");
X      break;
X
X    case '\t':
X    case ' ':
X    case 'q':
X      break;
X
X    case '\n':
X      fprintf (stdout,"test: ");
X      break;
X
X    default:
X      fprintf (stderr, "No such option (try ?).\n");
X      fflush (stderr);
X      break;
X    };
X  };
X
X  fclose (command);
X  exit (0);
X};
X
X
X
X
X
X
X
X
X
X
X
THE-END-OF:problem/ptest.c
if test 1736 -ne `wc -c <'problem/ptest.c'`; then
  echo shar: \"'problem/ptest.c'\" unpacked with wrong size!
fi
# end of 'problem/ptest.c'
fi
if test -f 'problem/Makefile' -a "${1}" != "-c"; then
echo shar: Will not clobber existing file \"'problem/Makefile'\"
else
echo shar: Extracting \"'problem/Makefile'\" \( 202 characters \)
sed "s/^X//" > 'problem/Makefile' << 'THE-END-OF:problem/Makefile'
XCC = cc
XCFLAGS = -g -lmpc
XDEFS =  -DNPROCS=4 -DWATCH_GR_OSVIEW
X
X
Xall: ptest
X
Xptest: ptest.c
X	$(CC) ptest.c $(DEFS) $(CFLAGS) -o ptest
X
Xclean:
X	-/bin/rm -f a.out ptest
X	-/bin/rm -f *~
X	-/bin/rm -f *.o
X
X
THE-END-OF:problem/Makefile
if test 202 -ne `wc -c <'problem/Makefile'`; then
  echo shar: \"'problem/Makefile'\" unpacked with wrong size!
fi
# end of 'problem/Makefile'
fi
if test -f 'problem/example_0' -a "${1}" != "-c"; then
echo shar: Will not clobber existing file \"'problem/example_0'\"
else
echo shar: Extracting \"'problem/example_0'\" \( 14 characters \)
sed "s/^X//" > 'problem/example_0' << 'THE-END-OF:problem/example_0'
Xh h h h
X?
Xh
Xq
THE-END-OF:problem/example_0
if test 14 -ne `wc -c <'problem/example_0'`; then
  echo shar: \"'problem/example_0'\" unpacked with wrong size!
fi
# end of 'problem/example_0'
fi
if test -f 'problem/example_1' -a "${1}" != "-c"; then
echo shar: Will not clobber existing file \"'problem/example_1'\"
else
echo shar: Extracting \"'problem/example_1'\" \( 10 characters \)
sed "s/^X//" > 'problem/example_1' << 'THE-END-OF:problem/example_1'
Xh
Xh
Xa
Xh
Xq
THE-END-OF:problem/example_1
if test 10 -ne `wc -c <'problem/example_1'`; then
  echo shar: \"'problem/example_1'\" unpacked with wrong size!
fi
# end of 'problem/example_1'
fi
if test -f 'problem/README' -a "${1}" != "-c"; then
echo shar: Will not clobber existing file \"'problem/README'\"
else
echo shar: Extracting \"'problem/README'\" \( 122 characters \)
sed "s/^X//" > 'problem/README' << 'THE-END-OF:problem/README'
XFor amusement try:
X
Xdiogenes% ptest example_0	/* behaves nicely */
Xdiogenes% ptest example_1	/* does not behave nicely */
THE-END-OF:problem/README
if test 122 -ne `wc -c <'problem/README'`; then
  echo shar: \"'problem/README'\" unpacked with wrong size!
fi
# end of 'problem/README'
fi
echo shar: End of shell archive
exit 0