removed unused variable

[wxWidgets.git] / docs / latex / wx / tunicode.tex

diff --git a/docs/latex/wx/tunicode.tex b/docs/latex/wx/tunicode.tex
index 3dd9814926ea2dfa0e848ab637f383e9a721ca2d..aa491e32421d0c5e229a03d1d2754ed20636dfaf 100644 (file)
--- a/docs/latex/wx/tunicode.tex
+++ b/docs/latex/wx/tunicode.tex
@@ -19,23 +19,25 @@ characters from languages other than English.
 
 Starting with release 2.1 wxWindows has support for compiling in Unicode mode
 on the platforms which support it. Unicode is a standard for character
 
 Starting with release 2.1 wxWindows has support for compiling in Unicode mode
 on the platforms which support it. Unicode is a standard for character

-encoding which addreses the shortcomings of the previous, 8 bit standards, by
-using 16 bit for encoding each character. This allows to have 65536 characters
-instead of the usual 256 and is sufficient to encode all of the world
-languages at once. More details about Unicode may be found at {\tt www.unicode.org}.
+encoding which addresses the shortcomings of the previous, 8 bit standards, by
+using at least 16 (and possibly 32) bits for encoding each character. This
+allows to have at least 65536 characters (what is called the BMP, or basic
+multilingual plane) and possible $2^{32}$ of them instead of the usual 256 and
+is sufficient to encode all of the world languages at once. More details about
+Unicode may be found at {\tt www.unicode.org}.

 
 % TODO expand on it, say that Unicode extends ASCII, mention ISO8859, ...
 
 As this solution is obviously preferable to the previous ones (think of
 incompatible encodings for the same language, locale chaos and so on), many
 
 % TODO expand on it, say that Unicode extends ASCII, mention ISO8859, ...
 
 As this solution is obviously preferable to the previous ones (think of
 incompatible encodings for the same language, locale chaos and so on), many

-modern ooperating systems support it. The probably first example is Windows NT
+modern operating systems support it. The probably first example is Windows NT

 which uses only Unicode internally since its very first version.
 
 Writing internationalized programs is much easier with Unicode and, as the
 support for it improves, it should become more and more so. Moreover, in the
 Windows NT/2000 case, even the program which uses only standard ASCII can profit
 from using Unicode because they will work more efficiently - there will be no
 which uses only Unicode internally since its very first version.
 
 Writing internationalized programs is much easier with Unicode and, as the
 support for it improves, it should become more and more so. Moreover, in the
 Windows NT/2000 case, even the program which uses only standard ASCII can profit
 from using Unicode because they will work more efficiently - there will be no

-need for the system to convert all strings hte program uses to/from Unicode
+need for the system to convert all strings the program uses to/from Unicode

 each time a system call is made.
 
 \subsection{Unicode and ANSI modes}
 each time a system call is made.
 
 \subsection{Unicode and ANSI modes}


@@ -46,12 +48,14 @@ environment. A better solution is to write programs in such way that they may
 be compiled either in ANSI (traditional) mode or in the Unicode one.
 
 This can be achieved quite simply by using the means provided by wxWindows.
 be compiled either in ANSI (traditional) mode or in the Unicode one.
 
 This can be achieved quite simply by using the means provided by wxWindows.

-Basicly, there are only a few things to watch out for:
+Basically, there are only a few things to watch out for:

 
 \begin{itemize}
 \item Character type ({\tt char} or {\tt wchar\_t})
 \item Literal strings (i.e. {\tt "Hello, world!"} or {\tt '*'})
 \item String functions ({\tt strlen()}, {\tt strcpy()}, ...)
 
 \begin{itemize}
 \item Character type ({\tt char} or {\tt wchar\_t})
 \item Literal strings (i.e. {\tt "Hello, world!"} or {\tt '*'})
 \item String functions ({\tt strlen()}, {\tt strcpy()}, ...)

+\item Special preprocessor tokens ({\tt \_\_FILE\_\_}, {\tt \_\_DATE\_\_} 
+and {\tt \_\_TIME\_\_})

 \end{itemize}
 
 Let's look at them in order. First of all, each character in an Unicode
 \end{itemize}
 
 Let's look at them in order. First of all, each character in an Unicode


@@ -59,20 +63,27 @@ program takes 2 bytes instead of usual one, so another type should be used to
 store the characters ({\tt char} only holds 1 byte usually). This type is
 called {\tt wchar\_t} which stands for {\it wide-character type}.
 
 store the characters ({\tt char} only holds 1 byte usually). This type is
 called {\tt wchar\_t} which stands for {\it wide-character type}.
 

-Also, the string and character constants should be encoded on 2 bytes instead
-of one. This is achieved by using the standard C (and C++) way: just put the
-letter {\tt 'L'} after any string constant and it becomes a {\it long}
-constant, i.e. a wide character one. To make things a bit more readable, you
-are also allowed to prefix the constant with {\tt 'L'} instead of putting it
-after it.
+Also, the string and character constants should be encoded using wide
+characters ({\tt wchar\_t} type) which typically take $2$ or $4$ bytes instead
+of {\tt char} which only takes one. This is achieved by using the standard C
+(and C++) way: just put the letter {\tt 'L'} after any string constant and it
+becomes a {\it long} constant, i.e. a wide character one. To make things a bit
+more readable, you are also allowed to prefix the constant with {\tt 'L'}
+instead of putting it after it.

 
 

-Finally, the standard C functions don't work with {\tt wchar\_t} strings, so
-another set of functions exists which do the same thing but accept 
+Of course, the usual standard C functions don't work with {\tt wchar\_t}
+strings, so another set of functions exists which do the same thing but accept

 {\tt wchar\_t *} instead of {\tt char *}. For example, a function to get the
 length of a wide-character string is called {\tt wcslen()} (compare with 
 {\tt strlen()} - you see that the only difference is that the "str" prefix
 {\tt wchar\_t *} instead of {\tt char *}. For example, a function to get the
 length of a wide-character string is called {\tt wcslen()} (compare with 
 {\tt strlen()} - you see that the only difference is that the "str" prefix

-standing for "string" has been replaced with "wcs" standing for
-"wide-character string").
+standing for "string" has been replaced with "wcs" standing for "wide-character
+string").
+
+And finally, the standard preprocessor tokens enumerated above expand to ANSI
+strings but it is more likely that Unicode strings are wanted in the Unicode
+build. wxWindows provides the macros {\tt \_\_TFILE\_\_}, {\tt \_\_TDATE\_\_} 
+and {\tt \_\_TTIME\_\_} which behave exactly as the standard ones except that
+they produce ANSI strings in ANSI build and Unicode ones in the Unicode build.

 
 To summarize, here is a brief example of how a program which can be compiled
 in both ANSI and Unicode modes could look like:
 
 To summarize, here is a brief example of how a program which can be compiled
 in both ANSI and Unicode modes could look like:


@@ -82,10 +93,14 @@ in both ANSI and Unicode modes could look like:
     wchar_t wch = L'*';
     const wchar_t *ws = L"Hello, world!";
     int len = wcslen(ws);
     wchar_t wch = L'*';
     const wchar_t *ws = L"Hello, world!";
     int len = wcslen(ws);

+
+    wprintf(L"Compiled at %s\n", __TDATE__);

 #else // ANSI
     char ch = '*';
     const char *s = "Hello, world!";
     int len = strlen(s);
 #else // ANSI
     char ch = '*';
     const char *s = "Hello, world!";
     int len = strlen(s);

+
+    printf("Compiled at %s\n", __DATE__);

 #endif // Unicode/ANSI
 \end{verbatim}
 
 #endif // Unicode/ANSI
 \end{verbatim}
 


@@ -115,25 +130,25 @@ a separate type for strings though, because the standard
 \helpref{wxString}{wxstring} supports Unicode, i.e. it stores either ANSI or
 Unicode strings depending on the compile mode.
 
 \helpref{wxString}{wxstring} supports Unicode, i.e. it stores either ANSI or
 Unicode strings depending on the compile mode.
 

-Finally, there is a special {\tt wxT()} macro which should enclose all literal
-strings in the program. As it's easy to see comparing the last fragment with
-the one above, this macro expands to nothing in the (usual) ANSI mode and
-prefixes {\tt 'L'} to its argument in the Unicode mode.
+Finally, there is a special \helpref{wxT()}{wxt} macro which should enclose all
+literal strings in the program. As it is easy to see comparing the last
+fragment with the one above, this macro expands to nothing in the (usual) ANSI
+mode and prefixes {\tt 'L'} to its argument in the Unicode mode.

 
 The important conclusion is that if you use {\tt wxChar} instead of 
 {\tt char}, avoid using C style strings and use {\tt wxString} instead and
 
 The important conclusion is that if you use {\tt wxChar} instead of 
 {\tt char}, avoid using C style strings and use {\tt wxString} instead and

-don't forget to enclose all string literals inside {\tt wxT()} macro, your
+don't forget to enclose all string literals inside \helpref{wxT()}{wxt} macro, your

 program automatically becomes (almost) Unicode compliant!
 
 Just let us state once again the rules:
 
 \begin{itemize}
 \item Always use {\tt wxChar} instead of {\tt char}
 program automatically becomes (almost) Unicode compliant!
 
 Just let us state once again the rules:
 
 \begin{itemize}
 \item Always use {\tt wxChar} instead of {\tt char}

-\item Always enclose literal string constants in {\tt wxT()} macro unless
-they're already converted to the right representation (another standard
-wxWindows macro {\tt \_()} does it, so there is no need for {\tt wxT()} in this
-case) or you intend to pass the constant directly to an external function
-which doesn't accept wide-character strings.
+\item Always enclose literal string constants in \helpref{wxT()}{wxt} macro
+unless they're already converted to the right representation (another standard
+wxWindows macro \helpref{\_()}{underscore} does it, for example, so there is no
+need for {\tt wxT()} in this case) or you intend to pass the constant directly
+to an external function which doesn't accept wide-character strings.

 \item Use {\tt wxString} instead of C style strings.
 \end{itemize}
 
 \item Use {\tt wxString} instead of C style strings.
 \end{itemize}
 


@@ -145,7 +160,7 @@ Although everything works fine inside the program, things can get nasty when
 it tries to communicate with the outside world which, sadly, often expects
 ANSI strings (a notable exception is the entire Win32 API which accepts either
 Unicode or ANSI strings and which thus makes it unnecessary to ever perform
 it tries to communicate with the outside world which, sadly, often expects
 ANSI strings (a notable exception is the entire Win32 API which accepts either
 Unicode or ANSI strings and which thus makes it unnecessary to ever perform

-any convertions in the program).
+any conversions in the program). GTK 2.0 only accepts UTF-8 strings.

 
 To get a ANSI string from a wxString, you may use the 
 mb\_str() function which always returns an ANSI
 
 To get a ANSI string from a wxString, you may use the 
 mb\_str() function which always returns an ANSI


@@ -156,5 +171,18 @@ useful, is wc\_str() function which always returns
 the Unicode string.
 
 % TODO describe fn_str(), wx_str(), wxCharBuf classes, ...
 the Unicode string.
 
 % TODO describe fn_str(), wx_str(), wxCharBuf classes, ...

-% Please remember to put a blank line at the end of each file! (Tex2RTF 'issue')
+
+\subsection{Unicode-related compilation settings}
+
+You should define {\tt wxUSE\_UNICODE} to $1$ to compile your program in
+Unicode mode. Note that it currently only works in Win32 and GTK 2.0 and
+that some parts of
+wxWindows are not Unicode-compliant yet (ODBC classes, for example). If you
+compile your program in ANSI mode you can still define {\tt wxUSE\_WCHAR\_T} 
+to get some limited support for {\tt wchar\_t} type.
+
+This will allow your program to perform conversions between Unicode strings and
+ANSI ones (using \helpref{wxMBConv classes}{mbconvclasses}) 
+and construct wxString objects from Unicode strings (presumably read
+from some external file or elsewhere).