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)