From 43dce07ee590d2275c6d0eaecad4f13662eb5a04 Mon Sep 17 00:00:00 2001
From: Ralph Castain <rhc@pmix.org>
Date: Tue, 28 Jan 2025 17:31:04 -0700
Subject: [PATCH] Add spawn_multiple test

Signed-off-by: Ralph Castain <rhc@pmix.org>
---
 .gitignore                |  1 +
 test/mpi/spawn_multiple.c | 54 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 test/mpi/spawn_multiple.c

diff --git a/.gitignore b/.gitignore
index de061bcb9a..a54e424721 100644
--- a/.gitignore
+++ b/.gitignore
@@ -191,6 +191,7 @@ test/spawn_multiple
 test/clichk
 test/chkfs
 
+test/mpi/spawn_multiple
 test/mpi/create_comm_from_group
 
 docs/_build
diff --git a/test/mpi/spawn_multiple.c b/test/mpi/spawn_multiple.c
new file mode 100644
index 0000000000..8905d1f5f3
--- /dev/null
+++ b/test/mpi/spawn_multiple.c
@@ -0,0 +1,54 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <mpi.h>
+
+int main(int argc, char* argv[])
+{
+    int msg;
+    MPI_Comm parent, child;
+    int rank, size;
+    char hostname[1024];
+    pid_t pid;
+    int i;
+    char *cmds[2];
+    char *argv0[] = { "foo", NULL };
+    char *argv1[] = { "bar", NULL };
+    char **spawn_argv[2];
+    int maxprocs[] = { 2, 2 };
+    MPI_Info info[] = { MPI_INFO_NULL, MPI_INFO_NULL };
+
+    cmds[1] = cmds[0] = argv[0];
+    spawn_argv[0] = argv0;
+    spawn_argv[1] = argv1;
+
+    MPI_Init(NULL, NULL);
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+    MPI_Comm_size(MPI_COMM_WORLD, &size);
+    MPI_Comm_get_parent(&parent);
+    /* If we get COMM_NULL back, then we're the parent */
+    if (MPI_COMM_NULL == parent) {
+        pid = getpid();
+        printf("Parent [pid %ld] about to spawn!\n", (long)pid);
+        MPI_Comm_spawn_multiple(2, cmds, spawn_argv, maxprocs,
+                                info, 0, MPI_COMM_WORLD,
+                                &child, MPI_ERRCODES_IGNORE);
+        printf("Parent done with spawn\n");
+        MPI_Comm_disconnect(&child);
+        printf("Parent disconnected\n");
+    }
+    /* Otherwise, we're the child */
+    else {
+        MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+        MPI_Comm_size(MPI_COMM_WORLD, &size);
+        gethostname(hostname, sizeof(hostname));
+        pid = getpid();
+        printf("Hello from the child %d of %d on host %s pid %ld: argv[1] = %s\n", rank, size, hostname, (long)pid, argv[1]);
+        MPI_Comm_disconnect(&parent);
+        printf("Child %d disconnected\n", rank);
+    }
+
+    MPI_Finalize();
+    return 0;
+}