mirror of
git://source.winehq.org/git/wine.git
synced 2024-10-31 10:41:12 +00:00
135 lines
4 KiB
Text
135 lines
4 KiB
Text
What is this?
|
|
------------
|
|
|
|
This note is a short description of
|
|
|
|
* How to port Wine to your favourite operating system
|
|
* Why you probably shouldn't use "#ifdef MyOS"
|
|
* What to do instead.
|
|
|
|
This document does not say a thing about how to port Wine to non-386
|
|
operating systems, though. You would need a CPU emulator. Let's get
|
|
Wine into a better shape on 386 first, OK?
|
|
|
|
|
|
|
|
|
|
Why "#ifdef MyOS" is probably a mistake.
|
|
---------------------------------------
|
|
|
|
Operating systems change. Maybe yours doesn't have the "foo.h"
|
|
header, but maybe a future version will have it. If you want
|
|
to "#include <foo.h>", it doesn't matter what operating system
|
|
you are using; it only matters whether "foo.h" is there.
|
|
|
|
Furthermore, operating systems change names or "fork" into
|
|
several ones. An "#ifdef MyOs" will break over time.
|
|
|
|
If you use the feature of Autoconf, the Gnu auto-configuration
|
|
utility wisely, you will help future porters automatically
|
|
because your changes will test for _features_, not names of
|
|
operating systems. A feature can be many things:
|
|
|
|
* existance of a header file
|
|
* existance of a library function
|
|
* existance of libraries
|
|
* bugs in header files, library functions, the compiler, ...
|
|
* (you name it)
|
|
|
|
You will need Gnu Autoconf, which you can get from your
|
|
friendly Gnu mirror. This program takes Wine's "configure.in"
|
|
file and produces a "configure" shell script that users use to
|
|
configure Wine to their system.
|
|
|
|
There _are_ exceptions to the "avoid #ifdef MyOS" rule. Wine,
|
|
for example, needs the internals of the signal stack -- that
|
|
cannot easily be described in terms of features.
|
|
|
|
Let's now turn to specific porting problems and how to solve
|
|
them.
|
|
|
|
|
|
|
|
MyOS doesn't have the `foo.h' header!
|
|
------------------------------------
|
|
|
|
This first step is to make Autoconf check for this header.
|
|
In configure.in you add a segment like this in the section
|
|
that checks for header files (search for "header files"):
|
|
|
|
AC_CHECK_HEADER(foo.h, AC_DEFINE(HAVE_FOO_H))
|
|
|
|
If your operating system supports a header file with the
|
|
same contents but a different name, say bar.h, add a check
|
|
for that also.
|
|
|
|
Now you can change
|
|
|
|
#include <foo.h>
|
|
|
|
to
|
|
|
|
#ifdef HAVE_FOO_H
|
|
#include <foo.h>
|
|
#elif defined (HAVE_BAR_H)
|
|
#include <bar.h>
|
|
#endif
|
|
|
|
If your system doesn't have a corresponding header file even
|
|
though it has the library functions being used, you might
|
|
have to add an "#else" section to the conditional. Avoid
|
|
this if you can.
|
|
|
|
You will also need to add "#undef HAVE_FOO_H" (etc.) to
|
|
include/config.h.in
|
|
|
|
Finish up with "make configure" and "./configure".
|
|
|
|
|
|
MyOS doesn't have the `bar' function!
|
|
------------------------------------
|
|
|
|
A typical example of this is the `memmove'. To solve this
|
|
problem you would add `memmove' to the list of functions
|
|
that Autoconf checks for. In configure.in you search for
|
|
AC_CHECK_FUNCS and add `memmove'. (You will notice that
|
|
someone already did this for this particular function.)
|
|
|
|
Secondly, you will also need to add "#undef HAVE_BAR"
|
|
to include/config.h.in
|
|
|
|
The next step depends on the nature of the missing function.
|
|
|
|
Case 1: It's easy to write a complete implementation of the
|
|
function. (`memmove' belongs to this case.)
|
|
|
|
You add your implementation in misc/port.c surrounded by
|
|
"#ifndef HAVE_MEMMOVE" and "#endif".
|
|
|
|
You might have to add a prototype for your function. If so,
|
|
include/miscemu.h might be the place. Don't forget to protect
|
|
that definition by "#ifndef HAVE_MEMMOVE" and "#endif" also!
|
|
|
|
Case 2: A general implementation is hard, but Wine is only using
|
|
a special case.
|
|
|
|
An example is the various "wait" calls used in SIGNAL_child
|
|
from loader/signal.c. Here we have a multi-branch case on
|
|
features:
|
|
|
|
#ifdef HAVE_THIS
|
|
...
|
|
#elif defined (HAVE_THAT)
|
|
...
|
|
#elif defined (HAVE_SOMETHING_ELSE)
|
|
...
|
|
#endif
|
|
|
|
Note that this is very different from testing on operating
|
|
systems. If a new version of your operating systems comes
|
|
out and adds a new function, this code will magically start
|
|
using it.
|
|
|
|
Finish up with "make configure" and "./configure".
|
|
|
|
|