OK FINALLY

CMakeLists.txt

@@ -12,7 +12,6 @@
 # publicly, and to permit others to do so.
 
 cmake_minimum_required(VERSION 3.14)
-set(CMAKE_CXX_STANDARD 17 CACHE BOOL "")
 
 project("singularity-opac"
       VERSION 0.0.1

cmake/SetupCompilers.cmake

@@ -6,7 +6,7 @@
 enable_language(CXX)
 include(CMakeDetermineCXXCompiler)
 
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 

cmake/SetupDeps.cmake

@@ -34,9 +34,8 @@ endif()
 # Can't play the target games above unless using
 # cmake 3.20+, so leave this one for now.
 # JMM: DO NOT SEARCH FOR HDF5 IF WE DON'T NEED IT
-# HDF5 WILL SUCK US ALL INTO HELL
-if (SPINER_USE_HDF)
-find_package(HDF5 COMPONENTS C HL QUIET)
+if (SINGULARITY_USE_HDF5)
+find_package(HDF5 COMPONENTS C HL)
 
 # findpackage doesnt export an interface for HDF5,
 # so create one
@@ -67,10 +66,22 @@ if (HDF5_FOUND)
       else()
 	message("MPI::MPI_CXX provided by parent package")
       endif()
+    else()
+      message(status "HDF5 is not parallel")
     endif()
+else()
+  message(STATUS "No HDF5")
 endif()
 endif()
 
+# JMM: I'm putting this here, as it depends on what happens with HDF5,
+# and I want that to be set AFTER we set all our options, so we don't
+# set HDF5 unnecessarily.
+cmake_dependent_option(SINGULARITY_USE_MPI
+        "Link to MPI"
+        ON "${SINGULARITY_USE_MPI};${HDF5_IS_PARALLEL}"
+        OFF)
+
 #=======================================
 # Setup Catch2
 # - provides Catch2::Catch2