wxWidgets/wxPython/BUILD.unix.txt

Building wxPython on Unix or Unix-like Systems
----------------------------------------------

The basic steps for building wxPython for Unix or Unix-like systems
are:

     1. Compile and/or install glib and gtk+
     2. Compile and/or install wxGTK
     3. Compile and install wxPython

We'll go into more detail of each of these steps below, but first a
few bits of background information on tools.

I use a tool called SWIG (http://www.swig.org) to help generate the
C++ sources used in the wxPython extension module.  However you don't
need to have SWIG unless you want to modify the *.i files.  I've made
several modifications to SWIG specific to wxPython's needs and so the
modified sources are included in the wx CVS at .../wxPython/wxSWIG.
If you need to modify the *.i files for wxPython then change to this
directory and run:

      configure
      make

(Do not run "make install" as wxswig is run in-place.)  You'll then
need to change a flag in the setup.py script as described below so the
wxPython build process will use SWIG if needed.

I use the new Python Distutils tool to build wxPython.  It is included
with Python 2.0, but if you want to use Python 1.5.2 or 1.6 then
you'll need to download and install Distutils 1.0 from
http://www.python.org/sigs/distutils-sig/

Okay, now on the the fun stuff...


1. Compile and/or install glib and gtk+
---------------------------------------

A. First of all, check and see if you've already got glib/gtk+ on your
   system, all the Linux distributions I know of come with it, at
   least as an option.  Look for libglib.* and libgtk.* in your system's
   standard library directories.  You'll also need the headers and
   config scripts in order to build things that use glib/gtk.  Try
   running gtk-config:

	   gtk-config --version

   If you have version 1.2.5 or better then you're all set.  You can
   skip to step #2.

B. If your system has a binary package mechanism, (RPMs, debs,
   whatever...) check and see if binaries for glib abd gtk+ are
   available.  Be sure to get the runtime library package as well as
   the development package, if they are separate.  Install them with
   your package tool, and skip to step #2.

C. If all else fails, you can get the source code for glib and gtk+ at
   http://www.gtk.org/.  Fetch the latest of each in the 1.2.x
   series.  Compile and install each of them like this:

	    gzip -d [package].tar.gz | tar xvf -
	    cd [package]
	    ./configure
	    make
	    make install

   The last step will probably have to be done as root.  Also, if your
   system needs anything done to update the dynamic loader for shared
   libraries, (such as running ldconfig on Linux) then do it after
   each library is installed.



2. Compile and/or install wxGTK
-------------------------------

A. You can find the sources and RPMs for wxGTK at
   http://wxwindows.org/, just follow the download links from the
   nevigation panel.  You can also check out a current snapshot of the
   sources from the CVS server.  (Some information about annonymous
   CVS access is at http://wxwindows.org/cvs.htm.)  The advantage of
   using CVS is that you can easily update as soon as the developers
   check in new sources or fixes.  The advantage of using a released
   version is that it usually has had more thorough testing done.  You
   can decide which method is best for you.

B. You'll usually want to use a version of wxGTK that has the same
   version number as the wxPython sources you are using.  (Another
   advantage of using CVS is that you'll get both at the same time.)

C. If using the RPMs be sure to get both the wxGTK and wxGTK-devel
   RPMs (at a minimum) and then install them as root.

	rpm -Uhv wxGTK-2.2.2-0.i386.rpm wxGTK-devel-2.2.2-0.i386.rpm

D. If using the sources (either from the tarball or from CVS) then
   configure it like this:

	cd wxWindows   # or whatever your top-level directory is called
	mkdir build
	cd build
	../configure --with-gtk

   There are gobs and gobs of options for the configure script, run
   ../configure --help to see them all.  I'll describe some that I find
   useful here.

   If you have OpenGL or compatible libraries installed, then add the
   --with-opengl flag.

   If you are on Solaris and are using a recent version of GCC, then
   you'll probably want to add the --enable-permissive flag so the
   compiler won't barf on your broken X11 header files.

   To make a debugging version of wxGTK, add the --enable-debug flag.
   This sets the -g flag for the compiler and also activates some
   special debugging code in wxWindows by defining the __WXDEBUG__
   macro.  You'll get some extra asserts, failure logging, etc.

   To make a static library and not make a shared library, use the
   --disable-shared and --enable-static flags.

   NOTE: There is a potential type mismatch between Python and wxGTK.
   This happens if Python defines some flags that turn on 64-bit file
   offset support and wxGTK does not.  This causes some basic types,
   like off_t, to be typedef'd differently causing the C++ method
   signatures to be incompatible and giving link errors at runtime.
   If you get errors upon running a wxPython script that looks
   something like this:

     SeekI_13wxInputStream10wxSeekMode: referenced symbol not found

   then that is probably the issue.  This can be fixed in the current
   code by predefining these flags before wxGTK's configure is run,
   for example:

     export CFLAGS="-D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DHAVE_LARGEFILE_SUPPORT"
     export CXXFLAGS=$CFLAGS
     ../configure --with-gtk --with-opengl --enable-debug

   In the 2.3.3 final release there will be a real configure flag for
   it, and it should be enabled by default.  You will be able to use
   --enable-largefile or --disable-largefile to control it.  If you
   still get this or a similar error with 2.3.3 then try disabling
   largefile support in GTK.

E. Now just compile and install.  You need to use GNU make, so if your
   system has something else get GNU make and build and install it and
   use it instead of your system's default make command.

       make
       make install

   The last step will probably have to be done as root.  Also, if your
   system needs anything done to update the dynamic loader for shared
   libraries, (such as running ldconfig on Linux) then do it now.

F. You can test your build by changing to one of the directories under
   build/samples or build/demos, running make and then running the
   executable that is built.



3. Compile and install wxPython
-------------------------------

A. You have the same options (and same advantages/disadvantages) for
   getting the wxPython source, either a released snapshot or from
   CVS.  The released version file is named wxPython-[version].tar.gz
   and is available at http://wxpython.org/download.php.  If you want
   to use CVS you'll find wxPython in the wxWindows CVS tree (see
   above) in the wxWindows/wxPython directory.

B. As mentioned previouslly, wxPython is built with the standard
   Python Distutils tool.  If you are using Python 2.0 or later you
   are all set, otherwise you need to download and install Distutils
   1.0 from http://www.python.org/sigs/distutils-sig/.

   On Unix systems Distutils figures out what commands and flags to
   use for the compiler and linker by looking in the Makefile that was
   used to build Python itself.  Most of the time this works okay.  If
   it doesn't, there doesn't seem to be a way to override the values
   that Distutils uses without hacking either Distutils itself, or
   Python's Makefile.  (Complain to the distutils-sig about this
   please.)  For example, on a Solaris system I had to edit
   /usr/local/lib/python1.5/config/Makefile and replace

         LDSHARED=ld -G

   with

         LDSHARED=gcc -G

   This particular problem has been fixed in Python 1.6 and beyond,
   but there may be similar issues on other platforms.

   While we're on the subject of how Python was built... Since
   wxPython is a C++ extension some platforms and/or compilers will
   require that the Python executable was linked with the C++ linker
   in order for everything to work correctly.  If you build and
   install Python yourself then this is easy to take care of,
   otherwise you may have to mess with binary packages or bribe your
   system administrator...

   In my case on Solaris wxPython applications would core dump on
   exit.  The core file indicated that the fault happened after
   _exit() was called and the run-time library was trying to execute
   cleanup code.  After relinking the Python executable the problem
   went away.  To build Python to link with the C++ linker do this:

         cd Python-2.0      # wherever the root of the source tree is
	 rm python          # in case it's still there from an old build
         make LINKCC=g++    # or whatever your C++ command is
	 make install

   I recently built Python 2.1.3 and Python 2.2.1 on Solaris and did
   not have to resort to this workaround so apparently thigns are
   getting better there.  I will leave this note here though in case
   there are similar issues elsewhere.  However I did run into a
   Python build issue that affects the wxPython build when attempting
   to use SunCC instead of GNU gcc.  See the note below titled
   "Building with non-GNU compilers" if you are interested.

C. Change to the root wxPython directory and look at the setup.py
   file.  This is the script that configures and defines all the
   information that Distutils needs to build wxPython.  There are some
   options near the begining of the script that you may want or need
   to change based on your system and what options you have selected
   up to this point, (sources from tar.gz or from CVS, etc.)  You can
   either change these flags directly in setup.py or supply them on
   the command-line.

	BUILD_GLCANVAS Set to zero if you don't want to build the
		       Open GL canvas extension module.  If you don't
		       have OpenGL or compatible libraries then you'll
		       need to set this to zero.

	     BUILD_OGL Set to zero if you don't want to build the
		       Object Graphics Library extension module.

  	     BUILD_STC Set to zero if you don't want to build the
		       wxStyledTextCtrl (the Scintilla wrapper)
		       extension module.

  	      USE_SWIG If you have edited any of the *.i files you
		       will need to set this flag to non-zero so SWIG
		       will be executed to regenerate the wrapper C++
		       and shadow python files.

	   IN_CVS_TREE If you are using the CVS version of the
		       wxWindows and wxPython sources then you will
		       need to set this flag to non-zero.  This is
		       needed because some source files from the
		       wxWindows tree are copied to be under the
		       wxPython tree in order to keep Distutils happy.
		       With this flag set then setup.py will
		       automatically keep these copied sources up to
		       date if the original version is ever updated.
		       If you are using the tar.gz version of the
		       Python sources then these copied sources are
		       already present in your source tree.


D. To build and install wxPython you simply need to execute the
   setup.py script.  If you have more than one version of Python
   installed, be sure to execute setup.py with the version you want to
   build wxPython for.  Depending on the permissions on your
   site-packages directory you may need to be root to run the install
   command.

	 python setup.py build
   	 python setup.py install

E. At this point you should be able to change into the wxPython/demo
   directory and run the demo:

	 python demo.py

F. If you would like to make a test build that doesn't overwrite the
   installed version of wxPython you can do so with this command
   instead of the install command above:

	 python setup.py build_ext --inplace

   This will build the wxPython package in the local wxPython
   directory instead of installing it under your Python installation.
   To run using this test version just add the base wxPython source
   directory to the PYTHONPATH:

         export PYTHONPATH=~/projects/wxWindows/wxPython
	 # or whatever is required for your shell
	 cd ~/projects/wxWindows/wxPython/demo
	 python demo.py



4. Building with non-GNU compilers
----------------------------------

As mentioned above Python's distutils uses whatever compiler Python
was compiled with to compile extension modules.  It also appears that
distutils assumes that this compiler can compile C or C++ sources as
distutils makes no differentiation between the two.  For builds using
GNU gcc and a few other compilers this is not an issue as they will
determine the type of souece from the file extension.  For SunCC (and
probably other compilers that came from cfront) it won't work as the C
compiler (cc) is totally separate from the C++ compiler (CC).  This
causes distutils to attempt to compile the wxPython sources with the C
compiler, which won't work.

There may be better ways to get around this, but here is the
workaround I devised.  I created a script that will execute either cc
or CC based on the file extension given to it.  If Python uses this
script for its compiler then it will also be used by extensions built
with distutils and everybody will be more or less happy.  Here is a
copy of the script I used.  It was a fairly quick rush job so there
are probably issues with it but it worked for me.

    #!/bin/bash
    #--------------------------------------------------------------
    # Try to determine type of file being compiled and then
    # launch cc for C sources or CC for C++.
    #

    args=$@
    is_C=

    for arg in $args; do

        # is the arg a file that exists?
        if [ -e $arg ]; then

            # does it end in ".c"?
            if [ "${arg:${#arg}-2}" == ".c" ]; then
                is_C=yes
            fi
        fi
    done

    # if the flag wasn't set then assume C++ and execute CC,
    # otherwise execute cc.
    if [ -z $is_C ]; then
        exec CC -w $@
    else
        exec cc -w $@
    fi
    #--------------------------------------------------------------

I called it pycc, put it in ${prefix}/bin and set its execute
permission bit.

The next step is to configure and build Python such that it uses pycc
as it's compiler.  You can do that by setting CC in your environment
before running configure, like this in bash:

    exoprt CC=pycc
    configure

After making and installing Python with this configuration you should
be able to build wxPython as described in the steps above.

-----------------
robin@alldunn.com