wxWidgets/docs/tech/tn0021.txt
Vadim Zeitlin 3f66f6a5b3 Remove all lines containing cvs/svn "$Id$" keyword.
This keyword is not expanded by Git which means it's not replaced with the
correct revision value in the releases made using git-based scripts and it's
confusing to have lines with unexpanded "$Id$" in the released files. As
expanding them with Git is not that simple (it could be done with git archive
and export-subst attribute) and there are not many benefits in having them in
the first place, just remove all these lines.

If nothing else, this will make an eventual transition to Git simpler.

Closes #14487.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74602 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
2013-07-26 16:02:46 +00:00

74 lines
2.8 KiB
Plaintext

How to add a new wxUSE_XXX preprocessor constant
================================================
0. Purpose
----------
Detailed description of what needs to be done when you want to add a new
wxUSE_XXX compilation flag. The text below assumes you need new wxUSE_FOO.
1. Overview
-----------
wxWidgets uses wxUSE_XXX macros for conditionally compiling in (or not)
optional components. In general, whenever a new non critical (i.e. not
absolutely required by important parts of the library) class Foo is added it
should use its own wxUSE_FOO compilation flag.
wxUSE_FOO must be always defined and have value of 0 or 1. Be careful with
testing for it in wx/foo.h: don't do it at the very beginning of the file
because then wxUSE_FOO would be not defined at all if the user directly
includes wx/foo.h, include "wx/defs.h" before testing for wxUSE_FOO.
2. Required files update
------------------------
Assuming wxUSE_FOO is used on all platforms, the following must be done:
a) update include/wx/setup_inc.h
This file contains all common wxUSE_XXXs, and is used to update wxMSW, wxMac
setup.h and Unix setup.h.in using build/update-setup-h. Please try to add
the new define in a logical place (i.e. near any related ones) and write a
detailed comment explaining what does it do and why would you want to turn
it on/off. Choose the appropriate default value: this should be usually 1
but can be 0 if there are some problems preventing the use of Foo by default
(e.g. it requires installation of some non standard 3rd party libraries).
After changing this file, run the update-setup-h script (this is probably
better done on a Unix machine although it should work under Cygwin too).
b) update other setup.h files
Currently include/wx/univ/setup.h and setup.h_vms are not automatically
updated so please update them manually (or modify the update-setup-h script
to take care of them...).
c) update configure.in
Here you need to add DEFAULT_wxUSE_FOO define. It should be added in the
block beginning after WX_ARG_CACHE_INIT line and should default to "no" for
"if DEBUG_CONFIGURE = 1" branch (this is used for absolutely minimal builds)
and the same as default value in setup_inc.h in the "else" branch.
You also need to add a WX_ARG_ENABLE (or, if new functionality can be
reasonably described as support for a 3rd party library, WX_ARG_WITH)
line togetherw with all the existing WX_ARG_ENABLEs.
If you have a sample/foo which should be only built when wxUSE_FOO==1,
then only add it to the SAMPLES_SUBDIRS if wxUSE_FOO=yes in configure.
3. Documentation
----------------
Currently wxUSE_XXXs are documented in docs/latex/wx/wxusedef.tex and a few
important global ones are in docs/latex/wx/cppconst.tex.
=== EOF ===
Author: VZ