1 files changed, 3 insertions(+), 23 deletions(-)

M Makefile

@@ 30,29 30,9 @@ ENABLE_JPEG = 1
 #ENABLE_HEIF = 1
 #ENABLE_PGSL = 1
 
-# NOTE **WARNING**
-#
-# You can uncomment the line below to enable support for HDF5 files.
-# However, notice that libHDF5 is an extremely user-hostile library and
-# linking to it has major drawbacks in exchange of being able to open the
-# stupid hdf5 files.  The real nightmare starts after version 1.10.3 of that
-# library, which is based on the "fabric" framework.  Thus, linking against
-# hdf5 turns each program into an "hdf5 application" that will perform
-# several "checks" each time the program is run.  These checks are triggered
-# by the mere dynamic loading of the library and cannot be disabled (even if
-# the program does not use the library at all!).  On my laptop, this takes
-# TWO HUNDRED FUCKING MILLISECONDS for each run of each program.  This is
-# easily way longer than most actual image-processing computations, slowing
-# all imscript-based pipelines to a crawl.  It's not that these checks do
-# anything useful, either : if you strace the runtime linking of hdf5, you'll
-# see that most of this time is spent in 961 calls to clock_nanosleep(2).
-#
-# My disappointment is immeasurable, and my day is ruined.
-#
-# On future versions of imscript, HDF5 support will be enabled by means of a
-# middleman library that dynamically links libhdf5 upon demand.  Thus, only
-# the first reading of an actual hdf5 image will be slowed-down.  But this
-# is a lot of work and it will have to wait.
+# CAVEAT: if you want to use HDF5, make sure that no "mpich" packages
+# are installed on your computer.  If they are, all programs that link
+# to libdf5 become really slow due to dynamic linking initialization.
 #
 #ENABLE_HDF5 = 1