sessions: add smoke test

.github/workflows/macos-checks.yaml

@@ -40,6 +40,7 @@ jobs:
         pushd examples
         make
         popd
-    - name: Test ring
+    - name: Test ring and sessions sanity check
       run: |
         mpirun --map-by ppr:1:core examples/ring_c
+        mpirun --map-by ppr:1:core examples/hello_sessions_c

examples/Makefile

@@ -65,14 +65,15 @@ EXAMPLES = \
 	 oshmem_max_reduction \
 	 oshmem_strided_puts \
 	 oshmem_symmetric_data \
-	 spc_example
+	 spc_example \
+         hello_sessions_c
 
 
 # Default target.  Always build the C MPI examples.  Only build the
 # others if we have the appropriate Open MPI / OpenSHMEM language
 # bindings.
 
-all: hello_c ring_c connectivity_c spc_example
+all: hello_c ring_c connectivity_c spc_example hello_sessions_c
 	@ if which ompi_info >/dev/null 2>&1 ; then \
 	    $(MAKE) mpi; \
 	fi
@@ -129,6 +130,8 @@ connectivity_c: connectivity_c.c
 	$(MPICC) $(CFLAGS) $(LDFLAGS) $? $(LDLIBS) -o $@
 spc_example: spc_example.c
 	$(MPICC) $(CFLAGS) $(LDFLAGS) $? $(LDLIBS) -o $@
+hello_sessions_c: hello_sessions_c.c
+	$(MPICC) $(CFLAGS) $(LDFLAGS) $? $(LDLIBS) -o $@
 
 hello_mpifh: hello_mpifh.f
 	$(MPIFC) $(FCFLAGS) $(LDFLAGS) $? $(LDLIBS) -o $@

examples/hello_sessions_c.c

@@ -0,0 +1,24 @@
+#include "mpi.h"
+#include <stdio.h>
+
+/*
+ * Simple test to demonstrate several aspects of MPI 4 Sessions and related
+ * functionality.  See sections 11.3 and 11.4 of the MPI 4 standard for more
+ * details.
+ */
+
+int main(int argc, char** argv) {
+  MPI_Info info;
+  MPI_Session s1, s2;
+
+#if 0
+/* need PR https://github.com/open-mpi/ompi/pull/12868 to be merged in
+ * before this can be uncommented.
+ */
+  MPI_Info_create(&info);
+#endif
+  MPI_Session_init(MPI_INFO_NULL, MPI_ERRORS_RETURN, &s1);
+  MPI_Session_finalize(&s1);
+  MPI_Session_init(MPI_INFO_NULL, MPI_ERRORS_RETURN, &s2);
+  MPI_Session_finalize(&s2);
+}