+Returns the number of characters copied to the buffer or -1 if there is not
+enough space.
+
+\wxheading{See also}
+
+\helpref{wxVsnprintf}{wxvsnprintf}, \helpref{wxString::Printf}{wxstringprintf}
+
+
+\membersection{wxT}\label{wxt}
+
+\func{wxChar}{wxT}{\param{char }{ch}}
+
+\func{const wxChar *}{wxT}{\param{const char *}{s}}
+
+wxT() is a macro which can be used with character and string literals (in other
+words, {\tt 'x'} or {\tt "foo"}) to automatically convert them to Unicode in
+Unicode build configuration. Please see the
+\helpref{Unicode overview}{unicode} for more information.
+
+This macro is simply returns the value passed to it without changes in ASCII
+build. In fact, its definition is:
+\begin{verbatim}
+#ifdef UNICODE
+#define wxT(x) L ## x
+#else // !Unicode
+#define wxT(x) x
+#endif
+\end{verbatim}
+
+
+\membersection{wxTRANSLATE}\label{wxtranslate}
+
+\func{const wxChar *}{wxTRANSLATE}{\param{const char *}{s}}
+
+This macro doesn't do anything in the program code -- it simply expands to the
+value of its argument (except in Unicode build where it is equivalent to
+\helpref{wxT}{wxt} which makes it unnecessary to use both wxTRANSLATE and wxT
+with the same string which would be really unreadable).
+
+However it does have a purpose and it is to mark the literal strings for the
+extraction into the message catalog created by {\tt xgettext} program. Usually
+this is achieved using \helpref{\_()}{underscore} but that macro not only marks
+the string for extraction but also expands into a
+\helpref{wxGetTranslation}{wxgettranslation} function call which means that it
+cannot be used in some situations, notably for static array
+initialization.
+
+Here is an example which should make it more clear: suppose that you have a
+static array of strings containing the weekday names and which have to be
+translated (note that it is a bad example, really, as
+\helpref{wxDateTime}{wxdatetime} already can be used to get the localized week
+day names already). If you write
+
+\begin{verbatim}
+static const wxChar * const weekdays[] = { _("Mon"), ..., _("Sun") };
+...
+// use weekdays[n] as usual
+\end{verbatim}
+
+the code wouldn't compile because the function calls are forbidden in the array
+initializer. So instead you should do
+
+\begin{verbatim}
+static const wxChar * const weekdays[] = { wxTRANSLATE("Mon"), ..., wxTRANSLATE("Sun") };
+...
+// use wxGetTranslation(weekdays[n])
+\end{verbatim}
+
+here.
+
+Note that although the code {\bf would} compile if you simply omit
+wxTRANSLATE() in the above, it wouldn't work as expected because there would be
+no translations for the weekday names in the program message catalog and
+wxGetTranslation wouldn't find them.
+
+\membersection{::wxVsnprintf}\label{wxvsnprintf}
+
+\func{int}{wxVsnprintf}{\param{wxChar *}{buf}, \param{size\_t }{len}, \param{const wxChar *}{format}, \param{va\_list }{argPtr}}
+
+The same as \helpref{wxSnprintf}{wxsnprintf} but takes a {\tt va\_list }
+argument instead of arbitrary number of parameters.
+
+Note that if \texttt{wxUSE\_PRINTF\_POS\_PARAMS} is set to 1, then this function supports
+positional arguments (see \helpref{wxString::Printf}{wxstringprintf} for more information).
+However other functions of the same family (wxPrintf, wxSprintf, wxFprintf, wxVfprintf,
+wxVfprintf, wxVprintf, wxVsprintf) currently do not to support positional parameters
+even when \texttt{wxUSE\_PRINTF\_POS\_PARAMS} is 1.
projects / wxWidgets.git / blobdiff