NAME

       pvm_reg_tasker - Register task as PVM task starter.

SYNOPSIS

       C    #include <pvmsdpro.h>

            int cc = pvm_reg_tasker()

       Fortran   Not Available

DESCRIPTION

       Registers  the  calling  task  as  a PVM task starter.  When a tasker is registered with a
       pvmd, and the pvmd receives a DM_EXEC message, instead of fork()ing and exec()ing the task
       itself,  it  passes a message to the tasker, which does the dirty work and sends a message
       back to the pvmd.

       Note:  If this doesn't make sense, don't worry about it.  This function is for  folks  who
       are  writing  stuff  like  debugger servers and so on.  For a more complete explanation of
       what's going on here, you should refer to the PVM source code and/or user guide section on
       implementation; this is only a man page.  That said...

       When  the  pvmd  receives a DM_EXEC message (request to exec new tasks), it searches epath
       (the PVM executable search path) for the file name.  If it finds the file, it then  either
       attempts  to start the processes (using fork() and exec()) or, if a tasker has registered,
       sends it a SM_STTASK message.

       The format of the SM_STTASK message is:
           int tid               // of task
           int flags             // as passed to spawn()
           string path           // absolute path of the executable
           int argc              // number of args to process
           string argv[argc]     // args
           int nenv              // number of envars to pass to task
           string env[nenv]      // environment strings

       The tasker must attempt to start the process when it gets  one  of  these  messages.   The
       tasker  doesn't  reply  to  the  pvmd  if  the task is successfully started; the task will
       reconnect to the pvmd on its own, using the cookie in envar PVMEPID to identify itself  to
       the pvmd.

       The  tasker  must  send  a  SM_TASKX  message  to the pvmd when any task that it owns (has
       started) exits, or if it can't start a  particular  task.   The  format  of  the  SM_TASKX
       message is:

           int tid               // of task
           int status            // the Unix exit status (from wait())
           int u_sec             // user time used by the task, seconds
           int u_usec            // microseconds
           int s_sec             // system time used by the task, seconds
           int s_usec            // microseconds

       The  tasker  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_tasker() returns PvmOk when successful.

SEE ALSO

       pvm_spawn(3PVM), pvm_tasks(3PVM),

                                          16 March, 1994                         REG_TASKER(3PVM)