From 2748878e9fd690bd10b5b613140b692df590af80 Mon Sep 17 00:00:00 2001
From: Jeff Squyres <jsquyres@cisco.com>
Date: Fri, 6 Feb 2004 04:20:13 +0000
Subject: [PATCH] Fix yet another linker error on OS X

This commit was SVN r655.
---
 src/mpi/communicator/communicator.h  |  3 +++
 src/mpi/communicator/lam_comm_init.c | 12 ++++++++++++
 src/tools/laminfo/laminfo.cc         | 17 +++++++++++++++--
 3 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/src/mpi/communicator/communicator.h b/src/mpi/communicator/communicator.h
index 3c37fd00c2..44f23caf0a 100644
--- a/src/mpi/communicator/communicator.h
+++ b/src/mpi/communicator/communicator.h
@@ -11,6 +11,7 @@
 #include "mpi/group/group.h"
 #include "mca/mpi/coll/coll.h"
 
+
 struct lam_communicator_t {
     char c_name[MPI_MAX_OBJECT_NAME];
     uint32_t c_contextid;
@@ -69,10 +70,12 @@ static inline lam_proc_t* lam_comm_lookup_peer(lam_communicator_t* comm, size_t
     return comm->c_remote_group->g_procs[peer_id];
 }
 
+
 #if defined(c_plusplus) || defined(__cplusplus)
 extern "C" {
 #endif
   int lam_comm_init(lam_communicator_t *comm);
+  int lam_comm_link_function(void);
 #if defined(c_plusplus) || defined(__cplusplus)
 }
 #endif
diff --git a/src/mpi/communicator/lam_comm_init.c b/src/mpi/communicator/lam_comm_init.c
index f9db51c44f..93620d364b 100644
--- a/src/mpi/communicator/lam_comm_init.c
+++ b/src/mpi/communicator/lam_comm_init.c
@@ -21,6 +21,18 @@ lam_communicator_t lam_mpi_comm_world;
 lam_communicator_t lam_mpi_comm_self;
 
 
+/*
+ * This function is here solely to allow non MPI progrlams be able to
+ * have the globals listed above linked in (e.g., laminfo).  According
+ * to POSIX, we have to link in a function to guarantee that we can
+ * get the global symbols in the relevant .o file.
+ */
+int lam_comm_link_function(void)
+{
+  return LAM_SUCCESS;
+}
+
+
 /*
  * This is a shell function that needs to be filled in.  It is here so
  * that this file will get linked into MPI executables (POSIX says
diff --git a/src/tools/laminfo/laminfo.cc b/src/tools/laminfo/laminfo.cc
index bc5303ff50..7d0c29d43b 100644
--- a/src/tools/laminfo/laminfo.cc
+++ b/src/tools/laminfo/laminfo.cc
@@ -19,6 +19,7 @@
 #include "lam/runtime/runtime.h"
 #include "lam/util/output.h"
 #include "lam/util/cmd_line.h"
+#include "mpi/communicator/communicator.h"
 #include "mca/lam/base/base.h"
 #include "tools/laminfo/laminfo.h"
 
@@ -224,14 +225,15 @@ laminfo::type_vector_t laminfo::mca_types;
 
 int main(int argc, char *argv[])
 {
-  int ret;
+  int ret = 0;
   bool acted = false;
   bool want_all = false;
 
   // Start LAM process
 
-  if (LAM_SUCCESS != lam_init(argc, argv))
+  if (LAM_SUCCESS != lam_init(argc, argv)) {
     return -1;
+  }
 
   // Initialize the argv parsing handle
 
@@ -265,6 +267,17 @@ int main(int argc, char *argv[])
   lam_cmd_line_make_opt(cmd_line, 'a', "all", 0, 
                         "Show all configuration options and MCA parameters");
 
+  // Call some useless functions in order to guarantee to link in some
+  // global variables.  Only check the return value so that the
+  // compiler doesn't optimize out the useless function.
+
+  if (LAM_SUCCESS != lam_comm_link_function()) {
+    // Stop .. or I'll say stop again!
+    ++ret;
+  } else {
+    --ret;
+  }
+
   // Get MCA parameters, if any */
   
   mca_base_open();