Building PLplot with a cross-compiler

From version 2.6.0 cmake includes support for cross-compiling. The CMake wiki provides a useful source of background information here.

Cross-compiling plplot is complicated because a full build involves lots of external libraries for different drivers and multiple different compilers /interpreters for the language bindings. However, it is possible to build a cut-down version of PLplot using cmake. PLplot compiles and runs several executables to create source files / data for the project at build time. Obviously it is not generally possible to run the cross-compiled versions and so access is also required to a native build tree in which to find the native versions of the build-time executables. Support for this was only added to PLplot on 3rd March 2009 (svn revision 9665).

The following instructions were written and tested on using the mingw32 cross-compiler for Windows running under Linux. Debian and Ubuntu supply packages for this environment so it is simple to install and test.

Build a native version of PLplot

This can just be a normal PLplot build. The only thing to be careful of it to ensure that it uses dynamic drivers if you intend to use them for the cross compiler otherwise get-drv-info will not be built.

Create a CMake toolchain

See the CMake wiki for details of this for individual platforms. The mingw32 example worked fine for me.

Building a cross-compiled version of PLplot

• Create a new directory for the cross-compile build and change to that directory.
• Run cmake.

• • You probably want to disable all languages and drivers by default and then just enable the ones you need. You can achieve this by setting DEFAULT_NO_DEVICES=ON and DEFAULT_NO_BINDINGS=ON. Failure to do this can lead to strange results if cmake picks up native rather than cross-compiler versions of tools, for example the fortran compiler, which are not part of your toolchain.
  • You will need to set the following CMake variables.
    • CMAKE_TOOLCHAIN_FILE: points to the CMake toolchain file for this cross-compiler.
    • CMAKE_NATIVE_BINARY_DIR: points to the top-level directory in the native PLplot build tree.
  • You will need to disable pkg-config support or ensure that pkg-config is using the correct package information files for the cross-platform. The simplest way of disabling this is by setting PKG_CONFIG_EXECUTABLE to something like NOT-FOUND.
  • You will either need to disable support for the CSA library, or explicitly set NanAwareCCompiler (probably to ON) since this uses a build-time executable to check for support. This can't be executed for a cross-compiled environment.

• Run make to build the cross-compiled version of PLplot.

Using this method I have successfully cross-compiled the C++ bindings and the ps and svg drivers. Note that neither of these has external dependencies. For reference the cmake command line looked like cmake -DCMAKE_TOOLCHAIN_FILE=~/Toolchain-mingw32.cmake -DDEFAULT_NO_DEVICES=ON -DPLD_ps=ON -DPLD_svg=ON -DPKG_CONFIG_EXECUTABLE=Not-Found -DDEFAULT_NO_BINDINGS=ON -DENABLE_cxx=ON -DNaNAwareCCompiler=ON -DCMAKE_NATIVE_BINARY_DIR=/home/andrew/software/plplot/build ../plplot