bionic (3) pvm_psend.3PVM.gz

NAME

       pvm_psend - Pack and send data in one call.

SYNOPSIS

       C    int info = pvm_psend( int tid, int msgtag, char *buf,
                                  int len, int datatype )

       Fortran   call pvmfpsend( tid, msgtag, buf, len, datatype,
                               info )

PARAMETERS

       tid     Integer task identifier of destination process.

       msgtag  Integer message tag supplied by the user.  msgtag should be >= 0.

       buf     Pointer to a buffer to send.

       len     Length of buffer (in multiple of data type size).

       datatype
               Type of data to which buf points (see below).

       info    Integer status code returned by the routine.

DESCRIPTION

       The routine pvm_psend takes a pointer to a buffer buf its length len and its data type datatype and sends
       this data directly to the PVM task identified by tid.  msgtag  is  used  to  label  the  content  of  the
       message.  If pvm_psend is successful, info will be 0. If some error occurs then info will be < 0.

       pvm_psend data can be received by pvm_precv, pvm_recv, pvm_trecv, or pvm_nrecv.

       The  pvm_psend  routine  is  asynchronous.   Computation  on the sending processor resumes as soon as the
       buffer is safe for reuse.  This is in contrast to synchronous communication, during which computation  on
       the sending processor halts until the matching receive is executed by the receiving processor.

       In  C  the  datatype  parameter  must  be one of the following, depending on the type of data to be sent:
       [Version 3.3.0 - This parameter only determines message length, not data conversion.  It only  sends  raw
       bytes]
           datatype    Data Type
           PVM_STR     string
           PVM_BYTE    byte
           PVM_SHORT   short
           PVM_INT     int
           PVM_FLOAT   real
           PVM_CPLX    complex
           PVM_DOUBLE  double
           PVM_DCPLX   double complex
           PVM_LONG    long integer
           PVM_USHORT  unsigned short int
           PVM_UINT    unsigned int
           PVM_ULONG   unsigned long int

       In Fortran the same data types specified for pack should be used.

       The  PVM  model  guarantees the following about message order.  If task 1 sends message A to task 2, then
       task 1 sends message B to task 2, message A will arrive at task 2 before message B.   Moreover,  if  both
       messages arrive before task 2 does a receive, then a wildcard receive will always return message A.

       pvm_psend  does  not affect the state of the current outgoing message buffer (created by pvm_initsend and
       used by pvm_send).

WARNINGS

       In some versions of PVM (CM5, I860 and PGON), messages sent using pvm_psend  must  be  received  only  by
       pvm_precv,  likewise  those  sent  with  pvm_send  must  be received by pvm_recv, pvm_nrecv or pvm_trecv.
       pvm_psend is not compatible with pvm_recv (nor pvm_send with pvm_precv).  In addition, pvm_probe  is  not
       interoperable with pvm_psend.

       This  problem  occurs  because  nonstandard  message  headers  are  used  for efficiency in the pvm_psend
       function.  In the generic Unix version of PVM, the calls are fully interoperable.

       The message tag space is shared between pvm_send and pvm_psend, so you must be careful to avoid selecting
       the wrong message (for example by using a wildcard to match the message).

EXAMPLES

       C:
           info = pvm_psend( tid, msgtag, array, 1000, PVM_FLOAT );

       Fortran:
           CALL PVMFPSEND( TID, MSGTAG, BUF, CNT, REAL4, INFO )

ERRORS

       These error conditions can be returned by pvm_psend

       PvmBadParam
              giving an invalid tid, msgtag, or datatype.

       PvmSysErr
              pvmd not responding.

SEE ALSO

       pvm_precv(3PVM), pvm_send(3PVM)

                                                 15 March, 1994                                      PSEND(3PVM)