pvm_recvf - Redefines the comparison function used to accept messages.
Contents
Description
The routine pvm_recvf defines the comparison function to be used by the pvm_recv, pvm_nrecv, and
pvm_probe functions. It is available as a means to customize PVM message passing. pvm_recvf sets a user
supplied comparison function to evaluate messages for receiving.
recvf returns the old value of the matching function, or 0 if the old function was the default matcher
pvm_recvf is intended for sophisticated C programmers who understand the function of such routines (like
signal) and who require a receive routine that can match on more complex message contexts than the
default provides.
Errors
No error conditions are returned by pvm_recvfExamples
Implementing message probe with recvf, using our matching function to return information in a global
variable.
#include <pvm3.h>
static int foundit = 0;
static int
foo_match(mid, tid, tag)
int mid;
int tid;
int tag;
{
int t, c;
struct pvmminfo header;
pvm_getminfo(mid, &header);
if ((tid == -1 || tid == header.src) && (tag == -1 || tag == header.tag))
foundit = 1;
return 0;
}
int
probe(src, tag)
{
int (*omatch)();
int cc;
omatch = pvm_recvf(foo_match);
foundit = 0;
if ((cc = pvm_nrecv(src, tag)) < 0)
return cc;
pvm_recvf(omatch);
return foundit;
}
Matching Function
The default comparison function evaluates the source and message tag associated with all incoming
messages.
Name
pvm_recvf - Redefines the comparison function used to accept messages.
Parameters
tid Integer task identifier of sending process supplied by the user.
tag Integer message tag supplied by the user.
bufid Integer message buffer identifier.
The matching function should return:
Value Action taken
< 0 Return immediately with this error code.
0 Do not pick this message.
1 Pick this message and do not scan the rest.
> 1 Pick this highest ranked message after
scanning them all.
See Also
pvm_bufinfo(3PVM), pvm_getminfo(3PVM), pvm_recv(3PVM), pvm_nrecv(3PVM), pvm_probe(3PVM), pvm_trecv(3PVM) 30 August, 1993 RECVF(3PVM)
Synopsis
Cint(*old)()=pvm_recvf(int(*new)(intbufid,inttid,inttag))FortranNOTAVAILABLE
