Overview
ODB API uses CMake for compilation and installation. This is a first step towards an homogenisation of the installation procedures for all ECMWF packages.
Like autotools, CMake will run some tests on the user's system to find out if required third-party software libraries are available and note their locations (paths). Based on this information it will produce the Makefiles needed to compile and install ODB API.
CMake is a cross-platform free software program for managing the build process of software using a compiler-independent method.
Generating the Makefiles with CMake
One nice and highly recommended feature of CMake is the ability to do out of source builds. In this way you can make all your ".o" files, various temporary depend files, and even the binary executables without cluttering up your source tree. To use out of source builds, first create a build directory, then change into your build directory and run cmake pointing it to the source directory and using your own options.
The command gives feedback on what requirements are fulfilled and what software is still required. The following table gives an overview of the different options. The default (without any options) will compile a shared library only and install it in /usr/local/.
| CMAKE_INSTALL_PREFIX | where you want to install your ODB API | /usr/local |
| CMAKE_BUILD_TYPE | to select the type of compilation:
| RelWithDebInfo |
| BUILD_SHARED_LIBS | Select the type of library built:
| ON |
| CMAKE_C_COMPILER | C Compiler | |
| CMAKE_C_FLAGS | Flags for the C Compiler | |
| CMAKE_Fortran_COMPILER | Fortran Compiler | |
| CMAKE_Fortran_FLAGS | Flags for the Fortran Compiler | |
| ENABLE_NETCDF | For the grib_to_netcdf convert tool | AUTO |
| ENABLE_PYTHON | Offers the Python interface to the package | AUTO |
| ENABLE_FORTRAN | Offers the Fortran interface to the package | AUTO |
cmake options | doc | default |
|---|
Note: The compilers can also be overridden by setting the environment variables CC and FC.
Note: To see the full output from the compilation, you can use:
make VERBOSE=1
Quick installation guide
Here is an example of a list of commands you could use to install ODB API. It is assumed “>” is the shell prompt.
> tar -xzf ODB_API-x.y.z-Source.tar.gz > mkdir build ; cd build > cmake -DCMAKE_INSTALL_PREFIX=/path/to/where/you/install/odb_api ../ODB_API-x.y.z-Source ... > make > ctest > make install
It is recommended that you always build in a clean directory and also install into a clean directory.