declare cmake hdf5_parallel option (future)

Author: scivision

cmake/hdf5.cmake

@@ -57,7 +57,7 @@ ${zlib_root}
 -DHDF5_ENABLE_PARALLEL:BOOL=$<BOOL:${hdf5_parallel}>
 -DMPI_ROOT:PATH=${MPI_ROOT}
 )
-# https://github.com/HDFGroup/hdf5/issues/818  for broken ph5diff
+# https://github.com/HDFGroup/hdf5/issues/818  for broken ph5diff in HDF5_BUILD_TOOLS
 
 ExternalProject_Add(HDF5
 URL ${hdf5_url}
@@ -82,6 +82,18 @@ target_link_libraries(HDF5::HDF5 INTERFACE "${HDF5_LIBRARIES}")
 
 add_dependencies(HDF5::HDF5 HDF5)
 
+# --- HDF5 parallel compression support
+# this could be improved by making it an ExternalProject post-build step instead of assumptions made here
+if(hdf5_parallel)
+  if(MPI_VERSION VERSION_GREATER_EQUAL 3)
+    message(STATUS "Building HDF5-MPI: MPI-3 available, assuming HDF5 parallel compression enabled")
+    set(hdf5_parallel_compression ".true." CACHE STRING "configure variable for HDF5 parallel compression")
+  else()
+    message(STATUS "Building HDF5-MPI: MPI-3 NOT available => HDF5 parallel compression disabled")
+    set(hdf5_parallel_compression ".false." CACHE STRING "configure variable for HDF5 parallel compression")
+  endif()
+endif(hdf5_parallel)
+
 # --- external deps
 find_package(Threads)
 

cmake/libraries.json

@@ -5,8 +5,7 @@
 },
 "zlib2": {
     "url" : "https://github.com/zlib-ng/zlib-ng/archive/refs/tags/2.0.5.tar.gz",
-    "sha256": "eca3fe72aea7036c31d00ca120493923c4d5b99fe02e6d3322f7c88dbdcd0085",
-    "git": "https://github.com/zlib-ng/zlib-ng.git"
+    "sha256": "eca3fe72aea7036c31d00ca120493923c4d5b99fe02e6d3322f7c88dbdcd0085"
 },
 "hdf5": {
     "1.13.0": {

cmake/options.cmake

@@ -1,4 +1,5 @@
 option(autobuild "auto-build HDF5 if missing/broken" on)
+option(hdf5_parallel "autobuild HDF5 parallel MPI")
 
 option(ENABLE_COVERAGE "Code coverage tests")
 

cmake/zlib.cmake

@@ -3,7 +3,6 @@
 
 include(ExternalProject)
 
-# need to be sure _ROOT isn't empty, defined is not enough
 if(NOT ZLIB_ROOT)
   set(ZLIB_ROOT ${CMAKE_INSTALL_PREFIX})
 endif()