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PSEND(3PVM) PVM Version 3.4 PSEND(3PVM) 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). datatypeType 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 identi- fied 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 proces- sor 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 compati- ble 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 effi- ciency 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)
NAME | SYNOPSIS | PARAMETERS | DESCRIPTION | WARNINGS | EXAMPLES | ERRORS | SEE ALSO
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