First step toward cancelation. We decided not to allow sends to be cancelled. For the others cases:

a completed request cannot be cancelled and a receive where the match was already realized cannot
be cancelled as well.

This commit was SVN r5295.

src/mca/pml/teg/src/pml_teg_cancel.c

@@ -1,3 +1,4 @@
+/* -*- Mode: C; c-basic-offset:4 ; -*- */
 /*
  * Copyright (c) 2004-2005 The Trustees of Indiana University.
  *                         All rights reserved.
@@ -18,16 +19,34 @@
 
 #include "pml_teg.h"
 
-
 int mca_pml_teg_cancel(ompi_request_t* request)
 {
+    mca_pml_base_request_t* teg_request = (mca_pml_base_request_t*)request;
+
+    if( true == request->req_complete ) {  /* way to late to cancel this one */
+        return OMPI_SUCCESS;
+    }
+    /* we dont cancel send requests by now */
+    if( MCA_PML_REQUEST_SEND == teg_request->req_type ) {
+        return OMPI_SUCCESS;
+    }
+    request->req_status._cancelled = true;
+    request->req_complete = true;  /* mark it as completed so all the test/wait  functions
+                                    * on this particular request will finish */
+    /* Now we have a problem if we are in a multi-threaded environment. We shou ld
+     * broadcast the condition on the request in order to allow the other threa ds
+     * to complete their test/wait functions.
+     */
+    if(ompi_request_waiting) {
+        ompi_condition_broadcast(&ompi_request_cond);
+    }
     return OMPI_SUCCESS;
 }
 
 int mca_pml_teg_cancelled(ompi_request_t* request, int* flag)
 {
     if(NULL != flag)
-        *flag = 0;
+        *flag = (true == request->req_status._cancelled ? 1 : 0);
     return OMPI_SUCCESS;
 }