Suppose you need to make a minor change to the Makefile in the test directory
(hdf5/test/Makefile). You have checked out hdf5 from the CVS repository into
~/scratch/hdf5. You want to build the library in a directory named
~/scratch/build.
First, edit the Makefile.am in the source tree. You must make any changes in the Makefile.am,
not the Makefile, since the Makefile is automatically generated.
cd ~/scratch/hdf5/test
vi Makefile.am
Now, go to the root of the source tree and run the reconfigure script, which updates the source tree. It will create a new Makefile.in in the test directory with your changes.
cd ~/scratch/hdf5
./bin/reconfigure
After running bin/reconfigure, you will want to test your change. Go to
~/scratch/build and run configure.
cd ~/scratch/build
../hdf5/configure
make check
Configure generates Makefiles from the Makefiles.in in the source tree. The dependencies are:
Makefile.am -> (bin/reconfigure) -> Makefile.in -> (configure) -> Makefile
Reconfigure should also be used when any change is made to configure.in.
Suppose you want to add the source file h5testfoo.c to the HDF5 test
library in the test directory. You open up test/Makefile.am in your
favorite text editor and scroll down until you see the line:
libh5test_la_SOURCES=h5test.c testframe.c
Just add h5testfoo.c to the list of sources. You're done!
Now run bin/reconfigure to create a new Makefile.in from the Makefile.am you just
edited.
Suppose you want to create a new test executable named newtest with one
source file, newtest.c. You open up test/Makefile.am and find
the line
TEST_PROG=testhdf5 lheap ohdr ...
Just add newtest to the list of programs. That's it! Automake will by
default guess that your program newtest has one source file named
newtest.c.
Now run bin/reconfigure to update the Makefile.in.
Suppose you want to create a new test executable named newertest with
several source files. You open up test/Makefile.am as before and find the line
TEST_PROG=testhdf5 lheap ohdr ...
Add newertest to the list of programs.
Now you need to tell Automake how to build newertest. Add a new line below
TEST_PROG:
newtest_SOURCES = source1.c source2.c source3.c
You don't need to mention header files, as these will be automatically detected.
Now run bin/reconfigure to update the Makefile.in.
For the most part, test scripts are handled like test programs, except that
they don't need to be compiled. You can specify a test script using the
check_SCRIPT variable:
TEST_SCRIPT=testh5dump.sh
${srcdir} variable.
TEST_SCRIPT=testh5dump.sh ${srcdir}/testh5dumpxml.sh
Scripts also need to be told which program they're testing. Do this using
the SCRIPT_DEPEND variable.
SCRIPT_DEPEND=h5dump${EXEEXT}
This way, whenever h5dump changes, the Makefile will know that
these test scripts need to be run again. After you make changes to a
Makefile.am, don't forget to run bin/reconfigure!
To add the directory for a new tool, h5merge, go to the Makefile.am
in the tools directory (the parent directory of the directory you want to add).
Find the line that reads
SUBDIRS=lib h5dump...
Add h5merge to this list of subdirectories.
Now you probably want to create a Makefile.am in the h5merge directory. A good starting
point for this Makefile.am might be the sample Makefile.am in the config directory
(config/Makefile.am.blank). Alternately, you could copy the Makefile.am
from another directory.
Once you have your new Makefile.am in place, edit configure.in in the root
directory. Near the end of the file is a list of files generated by configure.
Add tools/h5merge/Makefile.in to this list.
Now run bin/reconfigure. This will update configure and generate a Makefile.in in the
tools/h5merge directory. Don't forget to add both the Makefile.am and the Makefile.in to
CVS, and to update the manifest!.
Suppose you only want to compile a program when HDF5 is configured to run in
parallel--for example, a parallel version of h5repack called h5prepack.
Open up the h5repack Makefile.am
The simple solution is:
if BUILD_PARALLEL_CONDITIONAL
H5PREPACK=h5prepack
endif
Now the variable $H5PREPACK will be "h5prepack" if parallel is
enabled and "" if parallel is disabled. Add $H5PREPACK to the list of
programs to be built:
bin_PROGRAMS=h5repack $(H5PREPACK)
Add sources for this program as usual:
h5prepack_SOURCES=...
Don't forget to run bin/reconfigure when you're done!
Automake conditionals can be a very powerful tool. Suppose that instead of building
two versions of h5repack during a parallel build, you want to change the name of
the tool depending on whether or not HDF5 is configured to run in parallel--you
want to create either h5repack or h5prepack, but not both.
Open up the h5repack Makefile.am and use an automake conditional:
if BUILD_PARALLEL_CONDITIONAL
H5REPACK_NAME=h5prepack
else
H5REPACK_NAME=h5repack
endif
bin_PROGRAMS=$(H5REPACK_NAME)
Now you only build one program, but the name of that program changes. You still need to define sources for both h5repack and h5prepack, but you needn't type them out twice if they are the same:
h5repack_SOURCES=...
h5prepack_SOURCES=$(h5repack_SOURCES)
Don't forget to run bin/reconfigure when you're done!
Suppose you want to add a new library to the HDF5 build tree, libfoo. The procedure for building libraries is very similar to that for building programs:
lib_LTLIBRARIES=libfoo.la
libfoo_la_SOURCES=sourcefoo.c sourcefootwo.c
This library will be installed in the lib directory when a user types
"make install".
You might instead be building a convenience library for testing purposes (like
libh5test.la) and not want it to be installed. If this is the case, you
would type
check_LTLIBRARIES=libfoo.la
instead of
lib_LTLIBRARIES=libfoo.la
To make it easier for other directories to link to your library,
you might want to assign its path to a variable in all HDF5 Makefiles. You can
make changes to all Makefiles by editing config/commence.am and adding a line
like
LIBFOO=$(top_builddir)/foo/src/libfoo.la
config/commence.am is textually included in all Makefiles.am when automake
processes them.
As always, if you change a Makefile.am or config/commence.am, don't forget to run
bin/reconfigure.
If you have added or removed a function from HDF5, or if you have changed a
function signature, you should indicate this by updating the file
lt_vers.am located in the config directory. The
libtool shared library version number helps users who use HDF5 applications
to link dynamically against new versions of the library. Don't confuse
libtool's versioning system with HDF5's library version--the two numbers
are not related!
If you have changed the API at all, increment
LT_VERS_INTERFACE and set LT_VERS_REVISION to zero.
This tells users (and their linkers) that the interface has changed.
If you have added functions but not altered or removed existing ones,
also increment LT_VERS_AGE. The age of an interface is its
"backwards compatibility," the number of previous interfaces that can use
this interface. When you increase both the interface number and the age,
you are telling linkers that programs that could use the previous interface can
still use this one.
If instead you have altered or removed any functions, reset
LT_VERS_AGE to zero. Previous interfaces should not count on
being able to use this interface, since some functions might not be present
(or might have changed their signatures).
LT_VERS_REVISION is incremented when the library changes internally but the API does not. You shouldn't need to increment it, since this should be done automatically during a snapshot release.