docs/html/faqgtk.htm

   1
   2 <HTML>
   3
   4 <HEAD>
   5 <TITLE>wxWindows 2 for GTK FAQ</TITLE>
   6 </HEAD>
   7
   8 <BODY BGCOLOR=#FFFFFF TEXT=#000000 VLINK="#00376A" LINK="#00529C" ALINK="#313063">
   9
  10 <font face="Arial, Lucida Sans, Helvetica">
  11
  12 <table width=100% border=0 cellpadding=3 cellspacing=0>
  13 <tr>
  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>
  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>
  26 <h3>List of questions in this category</h3>
  27
  28 <ul>
  29 <li><a href="#wxgtk">What is wxWindows 2 for GTK+?</a></li>
  30 <li><a href="#locale">Why doesn&#39;t reading floating point numbers work when using wxWindows?</a></li>
  31 <li><a href="#gnome">Does wxGTK have GNOME support?</a></li>
  32 <li><a href="#redhat">Warning about GTK libraries supplied with RedHat</a></li>
  33 <li><a href="#bincompat">What range of Intel Linux platforms will a given application binary be usable on?</a></li>
  34 <li><a href="#static">Can I statically link the GTK+ library?</a></li>
  35 <li><a href="#charinframe">Why does my simple program using <tt>EVT_CHAR</tt> doesn't work?</a></li>
  36 </ul>
  37
  38 <hr>
  39
  40 <h3><a name="wxgtk">What is wxWindows 2 for GTK?</a></h3>
  41
  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
  47 <h3><a name="locale">Why doesn&#39;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&#39;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
  65 <h3><a name="gnome">Does wxGTK have GNOME support?</a></h3>
  66
  67 Currently wxGTK does not have any features that would involve dependence on any desktop
  68 environment&#39;s libraries, so it can work on GNOME, KDE and with other window managers
  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
  74 <h3><a name="redhat">Warning about GTK+ libraries supplied with RedHat</a></h3>
  75
  76 It seems that some versions of RedHat include a badly patched version of GTK+ (not wxGTK)
  77 which causes some trouble with wxWindows&#39; 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
  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)."
  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>
 111
 112 </font>
 113
 114 </BODY>
 115
 116 </HTML>