Merge pull request #653 from E3SM-Project/jayeshkrishna/disable_nczarr_by_default

Disable support for NCZarr by default.

Use PIO_ENABLE_NCZARR config flag to turn it on.

Author: jayeshkrishna

CMakeLists.txt

@@ -51,6 +51,7 @@ option (PIO_SAVE_DECOMPS     "Dump the decomposition information"           OFF)
 option (PIO_LIMIT_CACHED_IO_REGIONS  "Limit the number of non-contiguous regions in an IO process" OFF)
 option (WITH_PNETCDF         "Require the use of PnetCDF"                   ON)
 option (WITH_NETCDF          "Require the use of NetCDF"                    ON)
+option (PIO_ENABLE_NCZARR    "Enable support for NCZarr (via NetCDF)"       OFF)
 option (WITH_ADIOS2          "Require the use of ADIOS 2.x"                 OFF)
 option (WITH_HDF5            "Require the use of HDF5"                      OFF)
 option (ADIOS_BP2NC_TEST     "Enable testing of BP to NetCDF conversion"    OFF)

src/clib/CMakeLists.txt

@@ -112,12 +112,18 @@ if (WITH_NETCDF)
       PUBLIC ${NetCDF_C_LIBRARIES})
     if (${NetCDF_C_HAS_PARALLEL})
       set(PIO_USE_NETCDF4 1)
+      set(PIO_USE_NETCDF4_NCZARR 0)
       if (${NetCDF_C_HAS_NCZARR})
-        set(PIO_USE_NETCDF4_NCZARR 1)
-        target_compile_definitions (pioc
-          PUBLIC _SPIO_HAS_NETCDF4_NCZARR)
+        if (PIO_ENABLE_NCZARR)
+          message(STATUS "Enabling support for NCZarr")
+          set(PIO_USE_NETCDF4_NCZARR 1)
+          target_compile_definitions (pioc
+            PUBLIC _SPIO_HAS_NETCDF4_NCZARR)
+        else ()
+          message(STATUS "Disabling support for NCZarr (default)")
+        endif ()
       else ()
-        set(PIO_USE_NETCDF4_NCZARR 0)
+        message(STATUS "Disabling support for NCZarr (not supported)")
       endif ()
     else ()
       set(PIO_USE_NETCDF4 0)