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<b>wxWindows 2 for GTK FAQ</b>
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<P>

See also <a href="faq.htm">top-level FAQ page</a>.
<hr>
<h3>List of questions in this category</h3>

<ul>
<li><a href="#wxgtk">What is wxWindows 2 for GTK+?</a></li>
<li><a href="#locale">Why doesn&#39;t reading floating point numbers work when using wxWindows?</a></li>
<li><a href="#gnome">Does wxGTK have GNOME support?</a></li>
<li><a href="#redhat">Warning about GTK libraries supplied with RedHat</a></li>
<li><a href="#bincompat">What range of Intel Linux platforms will a given application binary be usable on?</a></li>
<li><a href="#static">Can I statically link the GTK+ library?</a></li>
<li><a href="#charinframe">Why does my simple program using <tt>EVT_CHAR</tt> doesn't work?</a></li>
</ul>

<hr>

<h3><a name="wxgtk">What is wxWindows 2 for GTK?</a></h3>

wxWindows 2 for GTK is a port of wxWindows to the <a href="http://www.gimp.org/gtk" target=_top>GTK+ toolkit</a>,
which is freely available for most flavours of Unix with X. wxWindows 2 for GTK is
often abbreviated to wxGTK. wxGTK has a separate home page <a href="http://www.freiburg.linux.de/~wxxt" target=_top>here</a>.
<P>

<h3><a name="locale">Why doesn&#39;t reading floating point numbers work when using wxWindows?</a></h3>

If your program reads the floating point numbers in the format <tt>123.45</tt>
from a file, it may suddently start returning just <tt>123</tt> instead of the
correct value on some systems -- which is all the more mysterious as the same
code in a standalone program works just fine.

<p>
The explanation is that GTK+ changes the current locale on program startup. If
the decimal point character in the current locale is not the period (for
example, it is comma in the French locale), all the standard C functions won&#39;t
recognize the numbers such as above as floating point ones any more.

<p>
The solution is to either use your own function for reading the floating point
numbers (probably the best one) or to call <tt>setlocale(LC_NUMERIC, "C")</tt>
before reading from file and restore the old locale back afterwards if needed.

<h3><a name="gnome">Does wxGTK have GNOME support?</a></h3>

Currently wxGTK does not have any features that would involve dependence on any desktop
environment&#39;s libraries, so it can work on GNOME, KDE and with other window managers
without installation hassles. Some GNOME and KDE integration features are file based, and
so may be added without dependence on libraries. Other features may be supported in the
future, probably as a separate library.
<P>

<h3><a name="redhat">Warning about GTK+ libraries supplied with RedHat</a></h3>

It seems that some versions of RedHat include a badly patched version of GTK+ (not wxGTK)
which causes some trouble with wxWindows&#39; socket code. Common symptoms are that when
a client tries to establish a connection to an existing server which refuses the request,
the client will get notified twice, first getting a LOST event and then a CONNECT event.
This problem can be solved by updating GTK with an official distribution of the library.
<P>

<h3><a name="bincompat">What range of Intel Linux platforms will a given application binary be usable on?</h3>

Robert Roebling replies:<P>

"The important thing is the libc version that your app
is linked against. The most recent version is 2.2.5
and programs linked against it will not run with version
2.1.X so that you will fare best if you compile your app
on a 2.1.X system. It will then run on practically all
Linux distros (if you link you app statically against
the image libraries and std C++ lib)."
<P>

<h3><a name="#static">Can I statically link the GTK+ library?</a></h3>

No, this is not possible. It leads to crashes in GTK+.
<P>

<h3><a name="#charinframe">Why does my simple program using
<tt>EVT_CHAR</tt> doesn't work?</a></h3>

In wxGTK, the frames never get focus and so can never receive <tt>CHAR</tt>
nor <tt>KEY</tt> events so an <tt>EVT_CHAR</tt> handler for a frame will be
never called. To receive these events, you should create a <tt>wxPanel</tt>
inside the frame and register the key event handlers for the panel, not the
frame.

<p>

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Commit	Line	Data
2b5f62a0	1
ce3ed50d JS	2	<HTML>
	3
	4	<HEAD>
	5	<TITLE>wxWindows 2 for GTK FAQ</TITLE>
	6	</HEAD>
	7
4e4dc03d	8	<BODY BGCOLOR=#FFFFFF TEXT=#000000 VLINK="#00376A" LINK="#00529C" ALINK="#313063">
ce3ed50d JS	9
	10	<font face="Arial, Lucida Sans, Helvetica">
	11
4e4dc03d	12	<table width=100% border=0 cellpadding=3 cellspacing=0>
ce3ed50d	13	<tr>
4e4dc03d JS	14	<td bgcolor="#004080" align=left height=24 background="images/bluetitlegradient.gif">
	15	<font size=+1 face="Arial, Lucida Sans, Helvetica" color="#FFFFFF">
	16	<b>wxWindows 2 for GTK FAQ</b>
ce3ed50d JS	17	</font>
	18	</td>
	19	</tr>
	20	</table>
	21
	22	<P>
	23
	24	See also <a href="faq.htm">top-level FAQ page</a>.
	25	<hr>
8b283bb8	26	<h3>List of questions in this category</h3>
4f3b37fd JS	27
4f3b37fd JS	28	<ul>
2b5f62a0	29	<li><a href="#wxgtk">What is wxWindows 2 for GTK+?</a></li>
4f3b37fd	30	<li><a href="#locale">Why doesn't reading floating point numbers work when using wxWindows?</a></li>
8b283bb8 JS	31	<li><a href="#gnome">Does wxGTK have GNOME support?</a></li>
8b283bb8 JS	32	<li><a href="#redhat">Warning about GTK libraries supplied with RedHat</a></li>
4f3b37fd	33	<li><a href="#bincompat">What range of Intel Linux platforms will a given application binary be usable on?</a></li>
2b5f62a0 VZ	34	<li><a href="#static">Can I statically link the GTK+ library?</a></li>
2b5f62a0 VZ	35	<li><a href="#charinframe">Why does my simple program using <tt>EVT_CHAR</tt> doesn't work?</a></li>
4f3b37fd	36	</ul>
53e112a0	37
8b283bb8	38	<hr>
ce3ed50d	39
4f3b37fd JS	40	<h3><a name="wxgtk">What is wxWindows 2 for GTK?</a></h3>
4f3b37fd JS	41
ce3ed50d JS	42	wxWindows 2 for GTK is a port of wxWindows to the <a href="http://www.gimp.org/gtk" target=_top>GTK+ toolkit</a>,
	43	which is freely available for most flavours of Unix with X. wxWindows 2 for GTK is
	44	often abbreviated to wxGTK. wxGTK has a separate home page <a href="http://www.freiburg.linux.de/~wxxt" target=_top>here</a>.
	45	<P>
	46
4f3b37fd JS	47	<h3><a name="locale">Why doesn't reading floating point numbers work when using wxWindows?</a></h3>
	48
	49	If your program reads the floating point numbers in the format <tt>123.45</tt>
	50	from a file, it may suddently start returning just <tt>123</tt> instead of the
	51	correct value on some systems -- which is all the more mysterious as the same
	52	code in a standalone program works just fine.
	53
	54	<p>
	55	The explanation is that GTK+ changes the current locale on program startup. If
	56	the decimal point character in the current locale is not the period (for
	57	example, it is comma in the French locale), all the standard C functions won't
	58	recognize the numbers such as above as floating point ones any more.
	59
	60	<p>
	61	The solution is to either use your own function for reading the floating point
	62	numbers (probably the best one) or to call <tt>setlocale(LC_NUMERIC, "C")</tt>
	63	before reading from file and restore the old locale back afterwards if needed.
	64
8b283bb8	65	<h3><a name="gnome">Does wxGTK have GNOME support?</a></h3>
ce3ed50d JS	66
ce3ed50d JS	67	Currently wxGTK does not have any features that would involve dependence on any desktop
8b283bb8	68	environment's libraries, so it can work on GNOME, KDE and with other window managers
ce3ed50d JS	69	without installation hassles. Some GNOME and KDE integration features are file based, and
	70	so may be added without dependence on libraries. Other features may be supported in the
	71	future, probably as a separate library.
	72	<P>
	73
2b5f62a0	74	<h3><a name="redhat">Warning about GTK+ libraries supplied with RedHat</a></h3>
8b283bb8	75
2b5f62a0	76	It seems that some versions of RedHat include a badly patched version of GTK+ (not wxGTK)
8b283bb8 JS	77	which causes some trouble with wxWindows' socket code. Common symptoms are that when
	78	a client tries to establish a connection to an existing server which refuses the request,
	79	the client will get notified twice, first getting a LOST event and then a CONNECT event.
	80	This problem can be solved by updating GTK with an official distribution of the library.
	81	<P>
	82
53e112a0 JS	83	<h3><a name="bincompat">What range of Intel Linux platforms will a given application binary be usable on?</h3>
	84
	85	Robert Roebling replies:<P>
	86
	87	"The important thing is the libc version that your app
	88	is linked against. The most recent version is 2.2.5
	89	and programs linked against it will not run with version
	90	2.1.X so that you will fare best if you compile your app
	91	on a 2.1.X system. It will then run on practically all
	92	Linux distros (if you link you app statically against
	93	the image libraries and std C++ lib)."
2b5f62a0 VZ	94	<P>
	95
	96	<h3><a name="#static">Can I statically link the GTK+ library?</a></h3>
	97
	98	No, this is not possible. It leads to crashes in GTK+.
	99	<P>
	100
	101	<h3><a name="#charinframe">Why does my simple program using
	102	<tt>EVT_CHAR</tt> doesn't work?</a></h3>
	103
	104	In wxGTK, the frames never get focus and so can never receive <tt>CHAR</tt>
	105	nor <tt>KEY</tt> events so an <tt>EVT_CHAR</tt> handler for a frame will be
	106	never called. To receive these events, you should create a <tt>wxPanel</tt>
	107	inside the frame and register the key event handlers for the panel, not the
	108	frame.
	109
	110	<p>
ce3ed50d JS	111
	112	</font>
	113
	114	</BODY>
	115
	116	</HTML>