pvm_getfds(3pvm) [debian man page]

GETFDS(3PVM)							  PVM Version 3.4						      GETFDS(3PVM)

NAME

       pvm_getfds - Get file descriptors in use by PVM.

SYNOPSIS

       C    int nfds = pvm_getfds( int **fds )

       Fortran	 Not Available

PARAMETERS

       fds     Returns integer array of file descriptors.

DESCRIPTION

       A PVM task uses sockets to communicate between libpvm and other tasks or the pvmd.  It is sometimes useful to know the file descriptor num-
       bers of the sockets in order to wait from input from either PVM messages or an external source.	For example, the PVM console waits on both
       keyboard  input	and  notify messages.  Input can be multiplexed by polling all sources, but this wastes cpu cycles.  Instead, the select()
       system call can be used to wait until one or more sources of input are ready.

       If it completes successfully, pvm_getfds returns the number of sockets in use, and the file descriptor numbers in an array  (allocated  and
       freed  by  libpvm).   At  least	one  socket always exists (from task to pvmd), and its descriptor is always fds[0].  The number of sockets
       varies as direct routes are established to other tasks.

       It can be difficult to track the set of file descriptors if direct routing is enabled, because routes are created as  messages  are  either
       sent or received.  The simplest approach is to disable direct routing.

       When  select  returns  with  a PVM file descriptor ready, a complete message may be ready to be received, or instead only a fragment may be
       waiting.  pvm_nrecv or pvm_probe should be used test without blocking.

RESTRICTIONS

       pvm_getfds is only available when running PVM on a Unix or similar system.

EXAMPLES

       The following program fragment waits until either keyboard input is available, or a PVM message has arrived.

	    int *d;
	    fd_set r;

	    pvm_setopt(PvmRoute, PvmDontRoute);
	    pvm_getfds(&d);

	    FD_ZERO(&r);
	    FD_SET(0, &r);
	    FD_SET(d[0], &r);
	    while(1) {
		 if (select(d[0] + 1, &r, (fd_set*)0, (fd_set*)0,
			    (struct timeval*)0) > 0) {
		      if (FD_ISSET(0, &r))
			   ...	  /* read keyboard input */
		      if (FD_ISSET(d[0], &r) && pvm_nrecv(-1, -1) > 0)
			   ...	  /* got a PVM message */
		 }
	    }

ERRORS

       The following error condition can be returned by pvm_getfds:

       PvmSysErr
	      pvmd not responding.

SEE ALSO

       pvm_notify(3PVM), pvm_trecv(3PVM)

								   22 Nov, 1994 						      GETFDS(3PVM)

REG_RM(3PVM)							  PVM Version 3.4						      REG_RM(3PVM)

NAME

       pvm_reg_rm - Register task as PVM resource manager.

SYNOPSIS

       C    #include <pvmsdpro.h>

	    int cc = pvm_reg_rm( struct pvmhostinfo **hip )
	    struct pvmhostinfo {
		 int  hi_tid;
		 char *hi_name;
		 char *hi_arch;
		 int  hi_speed;
	    };

       Fortran	 Not Available

PARAMETERS

       hostp  Returns pointer to a pvmhostinfo structure which contains information about the master host.

DESCRIPTION

       Registers  the  calling task as a PVM task and slave host manager.  This means it intercepts certain libpvm calls from other tasks in order
       to have a say in scheduling policy.  The resource manager will asynchronously receive messages from tasks containing requests for  service,
       as well as messages from pvmds notifying it of system failures.

       Before  you  start using this function, be warned that it's not a trivial thing, i.e. you can't just call it to turn off the default round-
       robin task assignment.  Rather, it allows you to write your own resource manager and hook it to PVM.

       To understand what the following messages mean, you should refer to the PVM source  code  and/or  user  guide  section  on  implementation;
       There's just too much to say about them.

       When one of the following libpvm functions is called in a task with resource manager set, the given message tag is sent to to resource man-
       ager.

	   Libpvm call		 RM message	   Normal message
	   pvm_addhosts()	 SM_ADDHOST	   TM_ADDHOST
	   pvm_config() 	 SM_CONFIG	   TM_CONFIG
	   pvm_delhosts()	 SM_DELHOST	   TM_DELHOST
	   pvm_notify() 	 SM_NOTIFY	   TM_NOTIFY
	   pvm_spawn()		 SM_SPAWN	   TM_SPAWN
	   pvm_tasks()		 SM_TASK	   TM_TASK
	   pvm_reg_rm() 	 SM_SCHED	   TM_SCHED

       The resource manager must in turn compose the following messages and send them to the pvmds:

	   RM message	     Normal message
	   SM_EXEC	     DM_EXEC
	   SM_EXECACK	     DM_EXECACK
	   SM_ADD	     DM_ADD
	   SM_ADDACK	     DM_ADDACK
	   SM_HANDOFF	     (none - change of resource manager)

       The following messages are sent asynchronously to the resource manager by the system:

	   RM message	     Meaning
	   SM_TASKX	     notify of task exit/fail
	   SM_HOSTX	     notify of host delete/fail

       The resource manager task must use pvm_setopt(PvmResvTids, 1) to allow sending reserved messages.  Messages should be packed using encoding
       PvmDataDefault to ensure they can be unpacked anywhere in the system.

       pvm_reg_rm() returns PvmOk when successful.

SEE ALSO

       pvm_addhosts(3PVM), pvm_config(3PVM), pvm_delhosts(3PVM), pvm_notify(3PVM), pvm_spawn(3PVM), pvm_tasks(3PVM)

								   4 March, 1994						      REG_RM(3PVM)