The purpose of this complete project is to provide a simple Fortran test case
consisting of a Fortran executable calling a single routine in an Fortran library
which prints out the classic "hello, world" phrase.

Here is how to test this project by hand.

1. Select Fortran compiler (gfortran in this case, but it could be any other Fortran
compiler with CMake support such as ifort or nagfor).

export FC=gfortran

2. By hand, build and test the project (with default shared library) in an initially empty build tree.

# Create and use an initially empty build tree.
mkdir build_dir
cd build_dir

# Following PATH change needed for Windows platforms only for the
# build-tree case.  (On such platforms, the library dll's are
# collected in the dll directory for the build-tree case.  If you test
# an installed version, the PATH manipulation should be different.
# See scripts/comprehensive_test.sh.)
PATH=$(pwd)/dll:$PATH

# Configure the test_fortran project with cmake.
cmake -DCMAKE_INSTALL_PREFIX=$(pwd)/install_tree -DBUILD_TEST=ON ..

# build Fortran library and executable that links to that library.
make hello

# Test the executable by running it.
# This should return the "hello, world" phrase
src_executable/hello

# This should supply a clean valgrind report
valgrind src_executable/hello

# Test linking of library and executable

# Most Unix-like platforms (including MinGW-w64/MSYS2? and definitely Cygwin, but excluding Mac OS X)
ldd -r src_lib/libhello.so >& ldd_lib.out
ldd -r src_executable/hello >& ldd_executable.out

# On Mac OS X
otool -L src_lib/libhello.so >& otool_lib.out
otool -L src_executable/hello >& otool_executable.out

Look through the generated *.out files for any error conditions.

N.B. on at least one platform (Cygwin) the -r option (which checks for
any undefined symbols) is not implemented yet (as of 2015-11) so you
will have to drop it for that special case until the Cygwin
ldd -r option is implemented.

3. Make more comprehensive test of this project with an automated script.
Note, for Windows platforms this script manipulates the PATH so that
the build-tree library dll will be found in the build-tree case, and the
installed library dll will be found in the install-tree case.

Check documentation of this comprehensive test script:

scripts/comprehensive_test.sh --help

This script is similar in concept but quite different (note its
different location) than the corresponding script in
../../scripts/comprehensive_test.sh which comprehensively tests all of
PLplot so do not confuse the two.

Actually do comprehensive test of Fortran language support (after
following step 1 above to select the compiler).  Normally this is done
as follows without any script options:

scripts/comprehensive_test.sh

For our two principal build configurations (shared libraries and
static libraries) this script (if executed without options) builds the
test_noninteractive target (which builds the "hello" executable and
all its prerequisites, runs that executable, and compares the output
of that executable with the expected output) in the build tree and in
the installed examples tree.

You check for errors in the above comprehensive test using

grep -i error ../../../comprehensive_test_fortran_disposeable/*/*/output_tree/*.out

and send whoever asked you to test CMake Fortran support with this
project the tarball of information that is collected by that script at
../../../comprehensive_test_fortran_disposeable/comprehensive_test.tar.gz

(4, optional) Debug result:
If (3) shows any errors than you can optionally debug the result as follows:

scripts/comprehensive_test.sh --do_trace yes

This produces voluminous results and buried (deeply) in those is
typically enough information to find out what is going wrong with the
CMake Fortran language support.  These voluminous results are automatically
included in the tarball report so please send that report (as well
as the one created without the --do_trace yes option in step 3) to whoever
asked you to test CMake Fortran support with this project.

In sum, this project provides a simple demonstration of how to use the
CMake Fortran language support with Fortran libraries that are either static
or shared. At the same time, this project tests the quality of CMake
Fortran support for various user's platforms.  If any user is having
trouble with CMake Fortran language support, they should run at least step
3 and step 4 above.