GLib is part of the GNOME git repository. At the current time, any
person with write access to the GNOME repository, can make changes to
GLib. This is a good thing, in that it encourages many people to work
on GLib, and progress can be made quickly. However, GLib is a fairly
large and complicated package that many other things depend on, so to
avoid unnecessary breakage, and to take advantage of the knowledge
about GLib that has been built up over the years, we'd like to ask
people committing to GLib to follow a few rules:

0) Ask first. If your changes are major, or could possibly break existing
   code, you should always ask. If your change is minor and you've
   been working on GLib for a while it probably isn't necessary
   to ask. But when in doubt, ask. Even if your change is correct,
   somebody may know a better way to do things.

   If you are making changes to GLib, you should be subscribed
   to gtk-devel-list@gnome.org. (Subscription address:
   gtk-devel-list-request@gnome.org.) This is a good place to ask
   about intended changes.

   #gtk+ on GIMPNet (irc.gimp.org, irc.us.gimp.org, irc.eu.gimp.org, ...)
   is also a good place to find GTK+ developers to discuss changes with,
   however, email to gtk-devel-list is the most certain and preferred
   method.

1) Ask _first_.

2) With git, we no longer maintain a ChangeLog file, but you are expected
   to produce a meaningful commit message. Changes without a sufficient
   commit message will be reverted. See below for the expected format
   of commit messages.

Notes:

* When developing larger features or complicated bug fixes, it is
  advisable to work in a branch in your own cloned GLib repository.
  You may even consider making your repository publically available
  so that others can easily test and review your changes.

* The expected format for git commit messages is as follows:

=== begin example commit ===
Short explanation of the commit

Longer explanation explaining exactly what's changed, whether any
external or private interfaces changed, what bugs were fixed (with bug
tracker reference if applicable) and so forth. Be concise but not too brief.
=== end example commit ===

  - Always add a brief description of the commit to the _first_ line of
    the commit and terminate by two newlines (it will work without the
    second newline, but that is not nice for the interfaces).

  - First line (the brief description) must only be one sentence and
    should start with a capital letter unless it starts with a lowercase
    symbol or identifier. Don't use a trailing period either. Don't exceed
    72 characters.

  - The main description (the body) is normal prose and should use normal
    punctuation and capital letters where appropriate. Normally, for patches
    sent to a mailing list it's copied from there.

  - When committing code on behalf of others use the --author option, e.g.
    git commit -a --author "Joe Coder <joe@coder.org>" and --signoff.


Owen Taylor
13 Aug 1998
17 Apr 2001

Matthias Clasen
31 Mar 2009

General Information
===================

This is GLib version @GLIB_VERSION@. GLib is the low-level core
library that forms the basis for projects such as GTK+ and GNOME. It
provides data structure handling for C, portability wrappers, and
interfaces for such runtime functionality as an event loop, threads,
dynamic loading, and an object system.

The official ftp site is:
  ftp://ftp.gtk.org/pub/glib

The official web site is:
  http://www.gtk.org/

Information about mailing lists can be found at
  http://www.gtk.org/mailinglists.html

To subscribe: mail -s subscribe gtk-list-request@gnome.org < /dev/null
(Send mail to gtk-list-request@gnome.org with the subject "subscribe")

Installation
============

See the file 'INSTALL'

Notes about GLib 2.20
=====================

^ The functions for launching applications (e.g. g_app_info_launch() +
  friends) now passes a FUSE file:// URI if possible (requires gvfs
  with the FUSE daemon to be running and operational). With gvfs 2.26,
  FUSE file:// URIs will be mapped back to gio URIs in the GFile
  constructors. The intent of this change is to better integrate
  POSIX-only applications, see bug #528670 for the rationale.  The
  only user-visible change is when an application needs to examine an
  URI passed to it (e.g. as a positional parameter). Instead of
  looking at the given URI, the application will now need to look at
  the result of g_file_get_uri() after having constructed a GFile
  object with the given URI.

Notes about GLib 2.18
=====================

* The recommended way of using GLib has always been to only include the
  toplevel headers glib.h, glib-object.h and gio.h. GLib enforces this by
  generating an error when individual headers are directly included.
  To help with the transition, the enforcement is not turned on by
  default for GLib headers (it is turned on for GObject and GIO).
  To turn it on, define the preprocessor symbol G_DISABLE_SINGLE_INCLUDES.

Notes about GLib 2.16
=====================

* GLib now includes GIO, which adds optional dependencies against libattr
  and libselinux for extended attribute and SELinux support. Use
  --disable-xattr and --disable-selinux to build without these.

Notes about GLib 2.10
=====================

* The functions g_snprintf() and g_vsnprintf() have been removed from
  the gprintf.h header, since they are already declared in glib.h. This
  doesn't break documented use of gprintf.h, but people have been known
  to include gprintf.h without including glib.h.

* The Unicode support has been updated to Unicode 4.1. This adds several
  new members to the GUnicodeBreakType enumeration.

* The support for Solaris threads has been retired. Solaris has provided
  POSIX threads for long enough now to have them available on every
  Solaris platform.

* 'make check' has been changed to validate translations by calling
  msgfmt with the -c option. As a result, it may fail on systems with
  older gettext implementations (GNU gettext < 0.14.1, or Solaris gettext).
  'make check' will also fail on systems where the C compiler does not
  support ELF visibility attributes.

* The GMemChunk API has been deprecated in favour of a new 'slice
  allocator'. See the g_slice documentation for more details.

* A new type, GInitiallyUnowned, has been introduced, which is
  intended to serve as a common implementation of the 'floating reference'
  concept that is e.g. used by GtkObject. Note that changing the
  inheritance hierarchy of a type can cause problems for language
  bindings and other code which needs to work closely with the type
  system. Therefore, switching to GInitiallyUnowned should be done
  carefully. g_object_compat_control() has been added to GLib 2.8.5
  to help with the transition.

Notes about GLib 2.6.0
======================

* GLib 2.6 introduces the concept of 'GLib filename encoding', which is the
  on-disk encoding on Unix, but UTF-8 on Windows. All GLib functions
  returning or accepting pathnames have been changed to expect
  filenames in this encoding, and the common POSIX functions dealing
  with pathnames have been wrapped. These wrappers are declared in the
  header <glib/gstdio.h> which must be included explicitly; it is not
  included through <glib.h>.

  On current (NT-based) Windows versions, where the on-disk file names
  are Unicode, these wrappers use the wide-character API in the C
  library. Thus applications can handle file names containing any
  Unicode characters through GLib's own API and its POSIX wrappers,
  not just file names restricted to characters in the system codepage.

  To keep binary compatibility with applications compiled against
  older versions of GLib, the Windows DLL still provides entry points
  with the old semantics using the old names, and applications
  compiled against GLib 2.6 will actually use new names for the
  functions. This is transparent to the programmer.

  When compiling against GLib 2.6, applications intended to be
  portable to Windows must take the UTF-8 file name encoding into
  consideration, and use the gstdio wrappers to access files whose
  names have been constructed from strings returned from GLib.

* Likewise, g_get_user_name() and g_get_real_name() have been changed
  to return UTF-8 on Windows, while keeping the old semantics for
  applications compiled against older versions of GLib.

* The GLib uses an '_' prefix to indicate private symbols that
  must not be used by applications. On some platforms, symbols beginning
  with prefixes such as _g will be exported from the library, on others not.
  In no case can applications use these private symbols. In addition to that,
  GLib+ 2.6 makes several symbols private which were not in any installed
  header files and were never intended to be exported.

* To reduce code size and improve efficiency, GLib, when compiled
  with the GNU toolchain, has separate internal and external entry
  points for exported functions. The internal names, which begin with
  IA__, may be seen when debugging a GLib program.

* On Windows, GLib no longer opens a console window when printing
  warning messages if stdout or stderr are invalid, as they are in
  "Windows subsystem" (GUI) applications. Simply redirect stdout or
  stderr if you need to see them.

* The child watch functionality tends to reveal a bug in many
  thread implementations (in particular the older LinuxThreads
  implementation on Linux) where it's not possible to call waitpid()
  for a child created in a different thread. For this reason, for
  maximum portability, you should structure your code to fork all
  child processes that you want to wait for from the main thread.

* A problem was recently discovered with g_signal_connect_object();
  it doesn't actually disconnect the signal handler once the object being
  connected to dies, just disables it. See the API docs for the function
  for further details and the correct workaround that will continue to
  work with future versions of GLib.

How to report bugs
==================

Bugs should be reported to the GNOME bug tracking system.
(http://bugzilla.gnome.org, product glib.) You will need
to create an account for yourself.

In the bug report please include:

* Information about your system. For instance:

   - What operating system and version
   - For Linux, what version of the C library

  And anything else you think is relevant.

* How to reproduce the bug.

  If you can reproduce it with one of the test programs that are built
  in the tests/ subdirectory, that will be most convenient.  Otherwise,
  please include a short test program that exhibits the behavior.
  As a last resort, you can also provide a pointer to a larger piece
  of software that can be downloaded.

* If the bug was a crash, the exact text that was printed out
  when the crash occured.

* Further information such as stack traces may be useful, but
  is not necessary.

Patches
=======

Patches should also be submitted to bugzilla.gnome.org. If the
patch fixes an existing bug, add the patch as an attachment
to that bug report.

Otherwise, enter a new bug report that describes the patch,
and attach the patch to that bug report.

Bug reports containing patches should include the PATCH keyword
in their keyword fields. If the patch adds to or changes the GLib
programming interface, the API keyword should also be included.

Patches should be in unified diff form. (The -u option to GNU
diff.)

Tor Lillqvist <tml@iki.fi>
Hans Breuer <hans@breuer.org>

The general parts, and the section about gcc and autoconfiscated build
are by Tor Lillqvist. The sections about MSVC build is by Hans Breuer.

General
=======

For prebuilt binaries (DLLs and EXEs) and developer packages (headers,
import libraries) of GLib, Pango, GTK+ etc for Windows, go to
http://www.gtk.org/download-windows.html . They are for "native"
Windows meaning they use the Win32 API and Microsoft C runtime library
only. No POSIX (Unix) emulation layer like Cygwin in involved.

To build GLib on Win32, you can use either gcc ("mingw") or the
Microsoft compiler and tools. For the latter, MSVC6 and later have
been used successfully. Also the Digital Mars C/C++ compiler have been
used.

People have also successfully cross-compiled GLib for Win32 from Linux
using the cross-mingw packages.

Note that to just *use* GLib on Windows, there is no need to build it
yourself.

On Windows setting up a correct build environment can be quite a task,
especially if you are used to just type "./configure; make" on Linux,
and expect things to work as smoothly on Windows.

The following preprocessor macros are to be used for conditional
compilation related to Win32 in GLib-using code:

- G_OS_WIN32 is defined when compiling for native Win32, without
  any POSIX emulation, other than to the extent provided by the
  bundled Microsoft C library (msvcr*.dll).

- G_WITH_CYGWIN is defined if compiling for the Cygwin
  environment. Note that G_OS_WIN32 is *not* defined in that case, as
  Cygwin is supposed to behave like Unix. G_OS_UNIX *is* defined by a GLib
  for Cygwin.

- G_PLATFORM_WIN32 is defined when either G_OS_WIN32 or G_WITH_CYGWIN
  is defined.

These macros are defined in glibconfig.h, and are thus available in
all source files that include <glib.h>.

Additionally, there are the compiler-specific macros:
- __GNUC__ is defined when using gcc
- _MSC_VER is defined when using the Microsoft compiler
- __DMC__ is defined when using the Digital Mars C/C++ compiler

G_OS_WIN32 implies using the Microsoft C runtime, normally
msvcrt.dll. GLib is not known to work with the older crtdll.dll
runtime, or the static Microsoft C runtime libraries libc.lib and
libcmt.lib. It apparently does work with the debugging version of
msvcrt.dll, msvcrtd.dll. If compiled with Microsoft compilers newer
than MSVC6, it also works with their compiler-specific runtimes, like
msvcr70.dll or msvcr80.dll. Please note that it's non totally clear if
you would be allowed by the license to distrubute a GLib linked to
msvcr70.dll or msvcr80.dll, as those are not part of the operating
system, but of the MSVC product. msvcrt.dll is part of Windows.

Building software that use GLib or GTK+
=======================================

Building software that just *uses* GLib or GTK+ also require to have
the right compiler set up the right way. If you intend to use gcc,
follow the relevant instructions below in that case, too.

Tor uses gcc with the -mms-bitfields flag which means that in order to
use the prebuilt DLLs (especially of GTK+), if you compile your code
with gcc, you *must* also use that flag. This flag means that the
struct layout rules are identical to those used by MSVC. This is
essential if the same DLLs are to be usable both from gcc- and
MSVC-compiled code. Such compatibility is desirable.

When using the prebuilt GLib DLLs that use msvcrt.dll from code that
uses other C runtimes like for example msvcr70.dll, one should note
that one cannot use such GLib API that take or returns file
descriptors. On Windows, a file descriptor (the small integer as
returned by open() and handled by related functions, and included in
the FILE struct) is an index into a table local to the C runtime
DLL. A file descriptor in one C runtime DLL does not have the same
meaning in another C runtime DLL.

Building GLib
=============

Again, first decide whether you really want to do this.

Before building GLib you must also have a GNU gettext-runtime
developer package. Get prebuilt binaries of gettext-runtime from
http://www.gtk.org/download-windows.html .

Autoconfiscated build (with gcc)
================================

Tor uses gcc 3.4.5 and the rest of the mingw utilities, including MSYS
from www.mingw.org. Somewhat earlier or later versions of gcc
presumably also work fine.

Using Cygwin's gcc with the -mno-cygwin switch is not recommended. In
theory it should work, but Tor hasn't tested that lately. It can
easily lead to confusing situations where one mixes headers for Cygwin
from /usr/include with the headers for native software one really
should use. Ditto for libraries.

If you want to use mingw's gcc, install gcc, win32api, binutils and
MSYS from www.mingw.org.

Tor invokes configure using:

CC='gcc -mtune=pentium3 -mthreads' CPPFLAGS='-I/opt/gnu/include' \
	LDFLAGS='-L/opt/gnu/lib -Wl,--enable-auto-image-base' CFLAGS=-O2 \
	./configure --disable-gtk-doc --prefix=$TARGET

The /opt/gnu mentioned contains the header files for GNU and (import)
libraries for GNU libintl. The build scripts used to produce the
prebuilt binaries are included in the "dev" packages.

Please note that the ./configure mechanism should not blindly be used
to build a GLib to be distributed to other developers because it
produces a compiler-dependent glibconfig.h. For instance, the typedef
for gint64 is long long with gcc, but __int64 with MSVC.

Except for this and a few other minor issues, there shouldn't be any
reason to distribute separate GLib headers and DLLs for gcc and MSVC6
users, as the compilers generate code that uses the same C runtime
library.

The DLL generated by either compiler is binary compatible with the
other one. Thus one either has to manually edit glibconfig.h
afterwards, or use the supplied glibconfig.h.win32 which has been
produced by running configure twice, once using gcc and once using
MSVC, and merging the resulting files with diff -D.

For MSVC7 and later (Visual C++ .NET 2003, Visual C++ 2005, Visual C++
2008 etc) it is preferred to use specific builds of GLib DLLs that use
the same C runtime as the code that uses GLib. Such DLLs should be
named differently than the ones that use msvcrt.dll.

For GLib, the DLL is called libglib-2.0-0.dll, and the import
libraries libglib-2.0.dll.a and glib-2.0.lib. Note that the "2.0" is
part of the "basename" of the library, it is not something that
libtool has added. The -0 suffix is added by libtool and is the value
of "LT_CURRENT - LT_AGE". The 0 is *not* part of the version number of
GLib, although, for GLib 2.x.0, it happens to be the same. The
LT_CURRENT - LT_AGE value will on purpose be kept as zero as long as
binary compatibility is maintained. For the gory details, see
configure.in and libtool documentation.

Cross-compiling
===============

It is possible to build GLib using a cross compiler. See
docs/reference/glib/html/glib-cross-compiling.html (part of the GLib
reference manual) for more information.

Building with MSVC
==================

If you are building from a SVN snapshot, you will not have any
makefile.msc files. You should copy the corresponding makefile.msc.in
file to that name, and replace any @...@ strings with the correct
value.

This is done automatically when an official GLib source distribution
package is built, so if you get GLib from a source distribution
package, there should be makefile.msc files ready to use (after some
editing).

The hand-written makefile.msc files, and the stuff in the "build"
subdirectory, produce DLLs and import libraries that match what the
so-called autoconfiscated build produces.

All the MSVC makefiles are for the command line build with nmake.  If
you want to use the VC-UI you can simply create wrapper .dsp makefiles
(read the VC docs how to do so).

Some modules may require Perl to auto-generate files. The goal (at
least Hans's) is to not require any more tools.

Build with:

nmake -f makefile.msc
  or
nmake -f makefile.msc DEBUG=1

[
 The former will create 'release' versions of the DLLs. If you
 plan to distribute you DLLs please use this command. The latter
 will create DLLs with debug information _and_ link them with
 msvcrtd.dll instead of msvcrt.dll.
 Beware: There are known problems with mixing DLLs in one
 application, which are build against different runtimes.
 Especially the index-to-file mapping used by 'unix-style' file
 operation - _open() _pipe() etc. - breaks sometimes in strange
 ways (for example the Gimp plug-in communication).
]

Required libraries (not build from svn)
------------------
  libintl (gnu-intl),

are available pre-built from the website mentioned above.

Versioning
----------
Instead of the Unix and auto* way of tracking versions and resolving
dependencies (configure; make; make install) involving autoconf,
automake, libtool and friends the MSVC build uses a different
approach.

The core of it's versioning is the file build/win32/module.defs.
It contains entries of the form MODULE_VER, e.g.:

	GLIB_VER = 2.0
	LIBICONV_VER = 1.3

and the placement of these modules defined as MODULE, e.g.:

	GLIB = $(TOP)/glib
	LIBICONV = $(TOP)/libiconv-$(LIBICONV_VER)

whereas TOP is defined as the relative path from the respective
module directory to your top build directory. Every makefile.msc
needs to define TOP before including the common make file part
make.msc, which than includes module.defs, like:

TOP = ../..
!INCLUDE $(TOP)/glib/build/win32/make.msc

(Taken from gtk+/gdk/makefile.msc)

With this provision it is possible to create almost placement
independent makefiles without requiring to 'install' the libraries and
headers into a common place (as it is done on Unix, and as Tor does
when producing his zipfiles with prebuilt GLib, GTK+ etc).

Special Files
-------------
	config.h.win32.in : @XXX_MAJOR_VERSION@ needs to be replaced by
the current version/build number. The resulting file is to be saved
as 'config.h.win32'. This should be automatically done if a package
gets build on the Unix platform.

	makefile.msc.in : @XXX_MAJOR_VERSION@ to be replaced. Save as
makefile.msc.

	<module>.def : every function which should be used from the outside of
a dll needs to be marked for 'export'. It is common that one needs to change
these files after some api changes occured. If there are variables to be
exported another mechanism is needed, like :

	#ifdef G_OS_WIN32
	#  ifdef GDK_COMPILATION
	#    define GDKVAR __declspec(dllexport)
	#  else
	#    define GDKVAR extern __declspec(dllimport)
	#  endif
	#else
	#  define GDKVAR extern
	#endif



Directory Structure
-------------------
all modules should be build in a common directory tree otherwise you
need to adapt the file 'module.defs'. They are listed here in increasing
dependencies order.

<common rootdir without spaces>
  |
  +- glib
  |   |
  |   +- build          : [this module lives in the SVN root dir]
  |   |   +- win32
  |   |       .\module.defs : defines (relative) locations of the headers
  |   |                       and libs and version numbers to be include
  |   |                       in dll names
  |   |       .\make.msc    : include by almost every 'makefile.msc'
  |   |
  |   | .\README.WIN32  : more information how to build
  |   | .\glibconfig.h.win32.in : similar to config.h.win32.in
  |   | .\makefile.msc  : master makefile, sub dir makefiles should work
  |   |
  |   +- glib
  |   +- gmodule
  |   +- gthread        : does _not_ depend on pthread anymore
  |   +- gobject
  |
  +- pango
  |   +- pango          : 'native' build does not require extra libs and
  |   |                 includes the minimal required text renderer
  |   |                 (there is also a currently slightly broken FreeType2
  |   |                 based implementation for win32)
  |   +- modules (not yet build)
  |
  +- atk
  |   +- atk
  |       .\makefile.msc : build here
  |
  +- gtk+
  |   | .\config.h.win32 : for all the below
  |   |
  |   +- gdk-pixbuf
  |   |   .\gdk_pixbuf.rc.in : version resource for the DLLs. Needs
  |   |                 to be converted (filled with version info)
  |   |                 as described above.
  |   |
  |   +- gdk
  |   |   | .\makefile.msc : some auto-generation is needed to build in the
  |   |   |             in the subdirectory
  |   |   +- win32
  |   |
  |   +- gtk

  |
  +- gimp
  |   .\makefile.msc    : master makefile to build The Gimp. The makefiles
  |                     from the sub dirs should work stand alone, but than
  |                     the user needs to know the build order

  |
  +- dia                : additionally depends on libart_lgpl (in SVN)
      |                 and libxml2 ( see http://www.xmlsoft.org/ )
      +- lib
      +- app
      +- objects
      +- plug-ins
          +- python