<hr>
-
+
@section includefiles Include files
-
+
The main include file is {\tt "wx/wx.h"}; this includes the most commonly
used modules of wxWidgets.
-
+
To save on compilation time, include only those header files relevant to the
source file. If you are using precompiled headers, you should include
the following section before any other includes:
-
+
@verbatim
// For compilers that support precompilation, includes "wx.h".
#include <wx/wxprec.h>
-
+
#ifdef __BORLANDC__
#pragma hdrstop
#endif
-
+
#ifndef WX_PRECOMP
// Include your minimal set of headers here, or wx.h
#include <wx/wx.h>
#endif
-
+
... now your other include files ...
@endverbatim
-
+
The file {\tt "wx/wxprec.h"} includes {\tt "wx/wx.h"}. Although this incantation
may seem quirky, it is in fact the end result of a lot of experimentation,
and several Windows compilers to use precompilation which is largely automatic for
and newer versions of GCC.
Some compilers might need extra work from the application developer to set the
build environment up as necessary for the support.
-
+
@section libraries Libraries
-
+
Most ports of wxWidgets can create either a static library or a shared
library. wxWidgets can also be built in multilib and monolithic variants.
See the \helpref{libraries list}{librarieslist} for more
information on these.
-
+
@section configuration Configuration
-
+
When using project files and makefiles directly to build wxWidgets,
options are configurable in the file
- \rtfsp{\tt "wx/XXX/setup.h"} where XXX is the required platform (such as msw, motif, gtk, mac). Some
+ \rtfsp{\tt "wx/XXX/setup.h"} where XXX is the required platform (such as msw, motif, gtk, mac). Some
settings are a matter of taste, some help with platform-specific problems, and
others can be set to minimize the size of the library. Please see the setup.h file
and {\tt install.txt} files for details on configuration.
-
+
When using the 'configure' script to configure wxWidgets (on Unix and other platforms where
configure is available), the corresponding setup.h files are generated automatically
along with suitable makefiles. When using the RPM packages
for installing wxWidgets on Linux, a correct setup.h is shipped in the package and
this must not be changed.
-
+
@section makefiles Makefiles
-
+
On Microsoft Windows, wxWidgets has a different set of makefiles for each
compiler, because each compiler's 'make' tool is slightly different.
Popular Windows compilers that we cater for, and the corresponding makefile
extensions, include: Microsoft Visual C++ (.vc), Borland C++ (.bcc),
OpenWatcom C++ (.wat) and MinGW/Cygwin (.gcc). Makefiles are provided
for the wxWidgets library itself, samples, demos, and utilities.
-
+
On Linux, Mac and OS/2, you use the 'configure' command to
generate the necessary makefiles. You should also use this method when
building with MinGW/Cygwin on Windows.
-
+
We also provide project files for some compilers, such as
Microsoft VC++. However, we recommend using makefiles
to build the wxWidgets library itself, because makefiles
can be more powerful and less manual intervention is required.
-
+
On Windows using a compiler other than MinGW/Cygwin, you would
build the wxWidgets library from the build/msw directory
which contains the relevant makefiles.
-
+
On Windows using MinGW/Cygwin, and on Unix, MacOS X and OS/2, you invoke
'configure' (found in the top-level of the wxWidgets source hierarchy),
from within a suitable empty directory for containing makefiles, object files and
libraries.
-
+
For details on using makefiles, configure, and project files,
please see docs/xxx/install.txt in your distribution, where
xxx is the platform of interest, such as msw, gtk, x11, mac.
-
+
@section windowsfiles Windows-specific files
-
+
wxWidgets application compilation under MS Windows requires at least one
extra file: a resource file.
-
+
@subsection resources Resource file
-
+
The least that must be defined in the Windows resource file (extension RC)
is the following statement:
-
+
@verbatim
#include "wx/msw/wx.rc"
@endverbatim
-
+
which includes essential internal wxWidgets definitions. The resource script
may also contain references to icons, cursors, etc., for example:
-
+
@verbatim
wxicon icon wx.ico
@endverbatim
-
+
The icon can then be referenced by name when creating a frame icon. See
the MS Windows SDK documentation.
-
+
\normalbox{Note: include wx.rc {\it after} any ICON statements
so programs that search your executable for icons (such
as the Program Manager) find your application icon first.}
-
+
@section allocatingobjects Allocating and deleting wxWidgets objects
-
+
In general, classes derived from wxWindow must dynamically allocated
with {\it new} and deleted with {\it delete}. If you delete a window,
all of its children and descendants will be automatically deleted,
so you don't need to delete these descendants explicitly.
-
+
When deleting a frame or dialog, use {\bf Destroy} rather than {\bf delete} so
that the wxWidgets delayed deletion can take effect. This waits until idle time
(when all messages have been processed) to actually delete the window, to avoid
problems associated with the GUI sending events to deleted windows.
-
+
Don't create a window on the stack, because this will interfere
with delayed deletion.
-
+
If you decide to allocate a C++ array of objects (such as wxBitmap) that may
be cleaned up by wxWidgets, make sure you delete the array explicitly
before wxWidgets has a chance to do so on exit, since calling {\it delete} on
array members will cause memory problems.
-
+
wxColour can be created statically: it is not automatically cleaned
up and is unlikely to be shared between other objects; it is lightweight
enough for copies to be made.
-
+
Beware of deleting objects such as a wxPen or wxBitmap if they are still in use.
Windows is particularly sensitive to this: so make sure you
make calls like wxDC::SetPen(wxNullPen) or wxDC::SelectObject(wxNullBitmap) before deleting
a drawing object that may be in use. Code that doesn't do this will probably work
fine on some platforms, and then fail under Windows.
-
+
@section architecturedependency Architecture dependency
-
+
A problem which sometimes arises from writing multi-platform programs is that
the basic C types are not defined the same on all platforms. This holds true
- for both the length in bits of the standard types (such as int and long) as
+ for both the length in bits of the standard types (such as int and long) as
well as their byte order, which might be little endian (typically
on Intel computers) or big endian (typically on some Unix workstations). wxWidgets
defines types and macros that make it easy to write architecture independent
code. The types are:
-
+
wxInt32, wxInt16, wxInt8, wxUint32, wxUint16 = wxWord, wxUint8 = wxByte
-
+
where wxInt32 stands for a 32-bit signed integer type etc. You can also check
which architecture the program is compiled on using the wxBYTE\_ORDER define
which is either wxBIG\_ENDIAN or wxLITTLE\_ENDIAN (in the future maybe wxPDP\_ENDIAN
as well).
-
+
The macros handling bit-swapping with respect to the applications endianness
are described in the \helpref{Byte order macros}{byteordermacros} section.
-
+
@section conditionalcompilation Conditional compilation
-
+
One of the purposes of wxWidgets is to reduce the need for conditional
compilation in source code, which can be messy and confusing to follow.
However, sometimes it is necessary to incorporate platform-specific
- features (such as metafile use under MS Windows). The \helpref{wxUSE\_*}{wxusedef}
+ features (such as metafile use under MS Windows). The \helpref{wxUSE\_*}{wxusedef}
symbols listed in the file {\tt setup.h} may be used for this purpose,
along with any user-supplied ones.
-
+
@section cpp C++ issues
-
+
The following documents some miscellaneous C++ issues.
-
+
@subsection templates Templates
-
+
wxWidgets does not use templates (except for some advanced features that
are switched off by default) since it is a notoriously unportable feature.
-
+
@subsection rtti RTTI
-
+
wxWidgets does not use C++ run-time type information since wxWidgets provides
its own run-time type information system, implemented using macros.
-
+
@subsection null Type of NULL
-
+
Some compilers (e.g. the native IRIX cc) define NULL to be 0L so that
no conversion to pointers is allowed. Because of that, all these
- occurrences of NULL in the GTK+ port use an explicit conversion such
+ occurrences of NULL in the GTK+ port use an explicit conversion such
as
-
+
{\small
@verbatim
wxWindow *my_window = (wxWindow*) NULL;
@endverbatim
}%
-
+
It is recommended to adhere to this in all code using wxWidgets as
this make the code (a bit) more portable.
-
+
@subsection precompiledheaders Precompiled headers
-
+
Some compilers, such as Borland C++ and Microsoft C++, support
precompiled headers. This can save a great deal of compiling time. The
recommended approach is to precompile {\tt "wx.h"}, using this
wxWidgets applications. For Windows compilers, two dummy source files
are provided (one for normal applications and one for creating DLLs)
to allow initial creation of the precompiled header.
-
+
However, there are several downsides to using precompiled headers. One
is that to take advantage of the facility, you often need to include
more header files than would normally be the case. This means that
changing a header file will cause more recompilations (in the case of
wxWidgets, everything needs to be recompiled since everything includes {\tt "wx.h"}!)
-
+
A related problem is that for compilers that don't have precompiled
headers, including a lot of header files slows down compilation
considerably. For this reason, you will find (in the common
the optimal compilation for each compiler, although it is
biased towards the precompiled headers facility available
in Microsoft C++.
-
+
@section filehandling File handling
-
+
When building an application which may be used under different
environments, one difficulty is coping with documents which may be
moved to different directories on other machines. Saving a file which
has pointers to full pathnames is going to be inherently unportable.
-
+
One approach is to store filenames on their own, with no directory
information. The application then searches into a list of standard
paths (platform-specific) through the use of \helpref{wxStandardPaths}{wxstandardpaths}.
-
+
Eventually you may want to use also the \helpref{wxPathList}{wxpathlist} class.
-
+
Nowadays the limitations of DOS 8+3 filenames doesn't apply anymore.
Most modern operating systems allow at least 255 characters in the filename;
- the exact maximum length, as well as the characters allowed in the filenames,
+ the exact maximum length, as well as the characters allowed in the filenames,
are OS-specific so you should try to avoid extremely long (> 255 chars) filenames
and/or filenames with non-ANSI characters.
-
+
Another thing you need to keep in mind is that all Windows operating systems
are case-insensitive, while Unix operating systems (Linux, Mac, etc) are
case-sensitive.
-
+
Also, for text files, different OSes use different End Of Lines (EOL).
Windows uses CR+LF convention, Linux uses LF only, Mac CR only.
-
+
The \helpref{wxTextFile}{wxtextfile},\helpref{wxTextInputStream}{wxtextinputstream},
\helpref{wxTextOutputStream}{wxtextoutputstream} classes help to abstract
from these differences.
Of course, there are also 3rd party utilities such as \tt{dos2unix} and \tt{unix2dos}
which do the EOL conversions.
-
- See also the \helpref{File Functions}{filefunctions} section of the reference
+
+ See also the \helpref{File Functions}{filefunctions} section of the reference
manual for the description of miscellaneous file handling functions.
-
+
*/
/*!
@page utilities_page Utilities and libraries supplied with wxWidgets
-
+
In addition to the \helpref{wxWidgets libraries}{librarieslist}, some
additional utilities are supplied in the \tt{utils} hierarchy.
-
+
For other user-contributed packages, please see the Contributions page
on the \urlref{wxWidgets Web site}{http://www.wxwidgets.org}.
-
+
\begin{description}\itemsep=0pt
\item[{\bf Helpview}]
Helpview is a program for displaying wxWidgets HTML
/*!
@page strategies_page Programming strategies
-
+
This chapter is intended to list strategies that may be useful when
writing and debugging wxWidgets programs. If you have any good tips,
please submit them for inclusion here.
<hr>
@section reducingerrors Strategies for reducing programming errors
-
+
@subsection useassert Use ASSERT
-
- It is good practice to use ASSERT statements liberally, that check for conditions
+
+ It is good practice to use ASSERT statements liberally, that check for conditions
that should or should not hold, and print out appropriate error messages.
-
+
These can be compiled out of a non-debugging version of wxWidgets
and your application. Using ASSERT is an example of `defensive programming':
it can alert you to problems later on.
-
+
See \helpref{wxASSERT}{wxassert} for more info.
-
+
@subsection usewxstring Use wxString in preference to character arrays
-
+
Using \helpref{wxString}{wxstring} can be much safer and more convenient than using wxChar *.
-
+
You can reduce the possibility of memory leaks substantially, and it is much more
convenient to use the overloaded operators than functions such as \tt{strcmp}.
- wxString won't add a significant overhead to your program; the overhead is compensated
+ wxString won't add a significant overhead to your program; the overhead is compensated
for by easier manipulation (which means less code).
-
+
The same goes for other data types: use classes wherever possible.
-
+
@section portability Strategies for portability
-
+
@subsection usesizers Use sizers
-
+
Don't use absolute panel item positioning if you can avoid it. Different GUIs have
very differently sized panel items. Consider using the \helpref{sizers}{sizeroverview} instead.
-
+
@subsection useresources Use wxWidgets resource files
-
+
Use .xrc (wxWidgets resource files) where possible, because they can be easily changed
independently of source code. See the \helpref{XRC overview}{xrcoverview} for more info.
-
+
@section debugstrategies Strategies for debugging
-
+
@subsection positivethinking Positive thinking
-
+
It is common to blow up the problem in one's imagination, so that it seems to threaten
weeks, months or even years of work. The problem you face may seem insurmountable:
but almost never is. Once you have been programming for some time, you will be able
to remember similar incidents that threw you into the depths of despair. But
remember, you always solved the problem, somehow!
-
+
Perseverance is often the key, even though a seemingly trivial problem
can take an apparently inordinate amount of time to solve. In the end,
you will probably wonder why you worried so much. That's not to say it
isn't painful at the time. Try not to worry -- there are many more important
things in life.
-
+
@subsection simplifyproblem Simplify the problem
-
+
Reduce the code exhibiting the problem to the smallest program possible
that exhibits the problem. If it is not possible to reduce a large and
complex program to a very small program, then try to ensure your code
doesn't hide the problem (you may have attempted to minimize the problem
in some way: but now you want to expose it).
-
+
With luck, you can add a small amount of code that causes the program
to go from functioning to non-functioning state. This should give a clue
to the problem. In some cases though, such as memory leaks or wrong
deallocation, this can still give totally spurious results!
-
+
@subsection usedebugger Use a debugger
-
+
This sounds like facetious advice, but it is surprising how often people
don't use a debugger. Often it is an overhead to install or learn how to
use a debugger, but it really is essential for anything but the most
trivial programs.
-
+
@subsection uselogging Use logging functions
-
+
There is a variety of logging functions that you can use in your program:
see \helpref{Logging functions}{logfunctions}.
-
+
Using tracing statements may be more convenient than using the debugger
in some circumstances (such as when your debugger doesn't support a lot
of debugging code, or you wish to print a bunch of variables).
-
+
@subsection usedebuggingfacilities Use the wxWidgets debugging facilities
-
+
You can use \helpref{wxDebugContext}{wxdebugcontext} to check for
memory leaks and corrupt memory: in fact in debugging mode, wxWidgets will
automatically check for memory leaks at the end of the program if wxWidgets is suitably
configured. Depending on the operating system and compiler, more or less
specific information about the problem will be logged.
-
+
You should also use \helpref{debug macros}{debugmacros} as part of a `defensive programming' strategy,
scattering wxASSERTs liberally to test for problems in your code as early as possible. Forward thinking
will save a surprising amount of time in the long run.
-
+
See the \helpref{debugging overview}{debuggingoverview} for further information.
*/
projects / wxWidgets.git / blobdiff