Metview's documentation is now on readthedocs!

Please go to https://metview.readthedocs.io/en/latest/

Overview

CodesUI uses CMake for its compilation and installation. This is part of the process of homogenising the installation procedures for all ECMWF packages.

CMake installation instructions

The CMake build system is used to build ECMWF software. The build process comprises two stages:

  1. CMake runs some tests on the system and finds out if required software libraries and headers are available. It uses this information to create native build tools (e.g. Makefiles) for the current platform.
  2. The actual build can take place, for example by typing 'make'.

Prerequisite

To install any ECMWF software package, CMake needs to be installed on your system. On most systems it will be already installed or this can be done through the standard package manager to install software. For further information to install CMake see

http://www.cmake.org/cmake/help/install.html

Directories

During a build with CMake there are three different directories involved: The source dir, the build dir and the install dir.


SourceContains the software's source code. This is where a source tarball should be extracted to./tmp/src/sw-package
BuildConfiguration and compiler outputs are generated here, including libraries and executables./tmp/build/sw-package
InstallWhere the software will actually be used from. Installation to this directory is the final stage./usr/local


Of these, the source and build directories can be anywhere on the system. The installation directory is usually left at its default, which is /usr/local. Installing software here ensures that it is automatically available to users. It is possible to specify a different installation directory by adding -DCMAKE_INSTALL_PREFIX=/path/to/install/dir to the CMake command line.

ECMWF software does not support in-source builds. Therefore the build directory cannot be (a subdirectory of) the source directory.

Quick Build Example

Here is an example set of commands to set up and build a software package using default settings. More detail for a customised build is given below.

# unpack the source tarball into a temporary directory
mkdir -p /tmp/src
cd /tmp/src
tar xzvf software-version-Source.tar.gz
 
# configure and build in a separate directory
mkdir -p /tmp/build
cd /tmp/build
cmake /tmp/src/software-version-Source
make

On a machine with multiple cores, compilation will be faster by specifying the number of cores to be used simultaneously for the build, for example:

make -j8

If the make command fails, you can get more output by typing:

make VERBOSE=1

If the build is successful, you can install the software:

make install

General CMake options

Various options can be passed to the CMake command. The following table gives an overview of some of the general options that can be used. Options are passed to the cmake command by prefixing them with -D, for example -DCMAKE_INSTALL_PREFIX=/path/to/dir.

CMAKE_INSTALL_PREFIX
where to install the software/usr/local
CMAKE_BUILD_TYPE

to select the type of compilation:

  • Debug
  • RelWithDebInfo
  • Release
  • Production
RelWithDebInfo
(release with debug info)
CMAKE_CXX_FLAGS
 Additional flags to pass to the C++ compiler 
CMAKE_C_FLAGS
Additional flags to pass to the C compiler 

The C and C++ compilers are chosen by CMake. This can be overwritten by setting the environment variables CC and CXX, before the call to cmake, to set the preferred compiler. Further the variable CMAKE_CXX_FLAGS can be used to set compiler flags for optimisation or debugging. For example, using CMAKE_CXX_FLAGS="-O2 -mtune=native" sets options for better optimisation. 

Finding support libraries

If any support libraries are installed in non-default locations, CMake can be instructed where to find them by one of the following methods. First, the option CMAKE_PREFIX_PATH can be set to a colon-separated list of base directories where the libraries are installed, for example -DCMAKE_PREFIX_PATH=/path/where/my/sw/is/installed. CMake will check these directories for any package it requires. This method is therefore useful if many support libraries are installed into the same location.

Debugging configure failures

If CMake fails to configure your project, run with debug logging first:

cmake -DECBUILD_LOG_LEVEL=DEBUG [...] /path/to/source

This will output lots of diagnostic information (in blue) on discovery of dependencies and much more.

Requirements to build CodesUI

The following table lists the dependencies CodesUI requires to be built from source. Please note, if you install these package from source you also might have to install the respective "-devel" packages.

Compilers
C++http://gcc.gnu.org/ 
Utilities

make

http://www.gnu.org/software/make/ 

Third party packages (best installed through system package manager)

Qthttp://www.qt.io/

minimum version 5.0.0 of Qt is required

bashhttps://www.gnu.org/software/bash/ 
ECMWF libraries
ecCodesecCodesminimum version 2.6.0. of ecCodes is required

CMake options used in CodesUI

CMake options are passed to the cmake command by prefixing them with -D, for example -DENABLE_QT_DEBUG=ON.

CMake option

Description

Default

ENABLE_QT_DEBUGoutputs additional log messages from Qt-based modulesOFF
Path options - only required when support libraries are not installed in default locations
CMake OptionDescriptionNotes
ECCODES_PATHpath to where ecCodes has been installed 
CMAKE_PREFIX_PATH

might be required if the Qt5 libraries are not found by default. Then they ican be specified like this: -DCMAKE_PREFIX_PATH=/path/to/qt5/


3 Comments

  1. paulmadejong

    For anyone running macOS Catalina and willing to install CodeSUI, the following Cmake command might help. This command points CMake to a QT5 directory installed through homebrew, sets the proper MacOS SDK sysroot (needed since Catalina changed the /usr/include location, check its location through 'xcrun --show-sdk-path' ), and avoids using clang and uses gcc and g++ instead. 

    cmake -DCMAKE_PREFIX_PATH=/usr/local/Cellar/qt/5.15.1/ 
          -DCMAKE_CXX_FLAGS='-std=c++11 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk' 
          -DCMAKE_C_FLAGS='-std=c++11 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk' 
          -DCMAKE_C_COMPILER=/usr/local/bin/gcc 
          -DCMAKE_CXX_COMPILER=/usr/local/bin/g++-10 
          /tmp/src/codes_ui-1.4.3-Source/


    1. Iain Russell

      Thanks Paul, that could be really useful! I'm surprised you need so many flags - I'm running Catalina and to build all of the Metview bundle (which basically includes CodesUI, I just have this:

      cmake  -DCMAKE_INSTALL_PREFIX=$HOME/dev/install/metview-bundle/debug \
       -DCMAKE_MODULE_PATH=$HOME/dev/git/ecbuild/cmake \
       -DCMAKE_BUILD_TYPE=Debug \
       -DPYTHON_EXECUTABLE=/usr/local/bin/python3 \
       -DCMAKE_PREFIX_PATH=/usr/local/Cellar/qt/5.14.1/ \
       -DENABLE_SSL=OFF -DENABLE_LAPACK=OFF \
       $HOME/dev/git/metview-bundle

      Actually, -DPYTHON_EXECUTABLE is probably not needed now with the latest version of Magics.

      But... I have not updated homebrew for a long time - that might be the difference.

      1. paulmadejong

        I had to point cmake to QT and the proper compilers as it would use Clang instead. Perhaps the -std=c++11 is no longer needed when using gcc and g++ (haven't tried) but the -isysroot was needed for me as the order of header inclusion is corrupted since I updated from Mojave to Catalina. It wouldn't build due to missing values in global namespace in cmath.h. Using the above, it build successfully at least (wink)