Problem 2562

Summary:	Build instructions don't work for examples.
Product:	Examples/Basic and Novice	Reporter:	Matt Bettencourt <mattb>
Component:	B1	Assignee:	Ivana Hrivnacova <ivana>
Status:	RESOLVED FIXED
Severity:	minor
Priority:	P4
Version:	11.1
Hardware:	All
OS:	All

Description Matt Bettencourt 2023-09-06 09:03:59 CEST

Looking at the instructions here

https://geant4-userdoc.web.cern.ch/Doxygen/examples_doc/html/README_HowToRun.html

When I attempt to follow these instructions, the build fails.

First.  I build and install Geant4 using the following commands.


cmake -DCMAKE_INSTALL_PREFIX=/home/mattb/Geant4/install -DGEANT4_INSTALL_DATA=ON -DGEANT4_INSTALL_DATADIR=/home/mattb/Geant4/data -DGEANT4_BUILD_MULTITHREADED=ON .. -GNinja

ninja
ninja install

and this works correctly to build install the code, and the examples.  Now I try to build the example

Just starting with the first example in /home/mattb/Geant4/install/share/Geant4/examples/basic/B1

mattb@0cb28a7-lcedt:~/Geant4/install/share/Geant4/examples/basic/B1$ mkdir build
mattb@0cb28a7-lcedt:~/Geant4/install/share/Geant4/examples/basic/B1$ cd build
mattb@0cb28a7-lcedt:~/Geant4/install/share/Geant4/examples/basic/B1/build$ cmake -DGeant4_DIR=/home/mattb/Geant4/install/lib/Geant4-11.1.2/ ..

-- The C compiler identification is GNU 11.4.0
-- The CXX compiler identification is GNU 11.4.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Error at CMakeLists.txt:13 (find_package):
  By not providing "FindGeant4.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Geant4", but
  CMake did not find one.

  Could not find a package configuration file provided by "Geant4" with any
  of the following names:

    Geant4Config.cmake
    geant4-config.cmake

  Add the installation prefix of "Geant4" to CMAKE_PREFIX_PATH or set
  "Geant4_DIR" to a directory containing one of the above files.  If "Geant4"
  provides a separate development package or SDK, be sure it has been
  installed.


-- Configuring incomplete, errors occurred!
See also "/home/mattb/Geant4/install/share/Geant4/examples/basic/B1/build/CMakeFiles/CMakeOutput.log".


These files exist but not in the expected location.  Attempting using make also fails.  All the examples seem to have this issue.

Comment 1 Ivana Hrivnacova 2023-09-06 11:09:40 CEST

Hello,

Thank you for reporting this.

The location of the cmake files in Geant4 installation has changed in Geant4 11.1, see the Relese Notes (https://geant4.web.cern.ch/download/release-notes/notes-v11.1.0.html):

3. Items for migration of the user code
...
- Using standard install location for CMake find_package configuration files under $CMAKE_INSTALL_PREFIX/lib/cmake/Geant4.
- Application builds using CMake will need to set Geant4_DIR to this new location, or use CMAKE_PREFIX_PATH, to find Geant4.

Please, use 

mattb@0cb28a7-lcedt:~/Geant4/install/share/Geant4/examples/basic/B1/build$ cmake -DGeant4_DIR=/home/mattb/Geant4/install/lib/cmake/Geant4/ ..

We will fix this information in the examples documentation.

Comment 2 Ivana Hrivnacova 2023-09-08 10:03:12 CEST

The documentation is fixed now.