    $Id: FAQ.xml,v 1.14 2002/04/07 11:00:04 sphair Exp $

# Frequently Asked Questions about the ClanLib Library

This document tries to answer questions a user might have when installing and using ClanLib. Please make sure you read this before sending questions or bug reports to the maintainers.

If you have any questions you think should be answered in this document, or find any errors or outdated information, please read the README document to find out where to direct your questions.

## Compiling under Linux

Question: | When I try to compile ClanLib, I get errors regarding that try, catch and throw are reserved C++ keywords.
Question: | My C++ compiler wants exceptions to be enabled with -fhandle-exceptions.
Question: | I get an "Internal compiler error" message from my C++ compiler.
Answer: | Try upgrading your compiler to a newer version.

Question: | When compiling it complains that it cannot open shared object libclanCore...
    error in loading shared libraries: libclanCore.so.0: cannot open shared object file: No such file or directory
Answer: | Chances are you installed the ClanLib libraries into /usr/local/lib, but /usr/local/lib isn't present in the /etc/ld.so.conf. You can choose to install in a directory that IS present in /etc/ld.so.conf or choose to add /usr/local/lib to /etc/ld.so.conf. Remember to run ldconfig as root afterwards.

Question: | I'm using PGCC, and I get error while compiling a file called virtch.c.
Question: | I'm using Mandrake 6.x or earlier, and I get error while compiling a file called virtch.c.
Answer: | Open Setup/Unix/makefile.conf, search for -O3 and replace it with -O6.

Question: | I'm using SuSE and am getting warnings about multiple common of...
    obj/Input.o: warning: multiple common of 'CL_InputAxis type_info node'
    /usr/local/lib/libclan.so: warning: previous common is here
Answer: | To get rid of those annoying "multiple common..." warnings edit /usr/lib/gcc-lib/i486-linux/egcs-???/specs. *lib -warn-common%{share.... should be: *lib %{share...

Question: | I'm using SuSE and cannot locate libz.so.
Answer: | zlib is called libgz.so on SuSE systems prior to 6.2. To fix, try this as root: ln -s /usr/lib/libgz.so /usr/lib/libz.so ldconfig It creates a symlink and updates the library cache.

Question: | My compiler dies with a 'MAP_FAILED undeclared' message.
Answer: | We've had reports from people using the Slackware Linux distribution that the compile fails because MAP_FAILED is undefined. This is supposed to be in sys/mman.h as a return value of mmap(), but apparently isn't on some systems. We don't know if this is a Slackware problem or a libc5/kernel issue, but feel free to enlighten us. Until then, we recommend pasting the following code into your /usr/include/sys/mman.h, or in some other headerfile if you prefer not to muck with your system header files (or don't have permissions?)
    #ifndef MAP_FAILED
    #define MAP_FAILED ((__ptr_t) -1)
    #endif

Question: | I use Slack 7 and getting errors about cannot specify -o with -c or -S...
          Sources/Core/Display/Generic/cliprect.cpp g++: cannot specify -o with -c
          or -S and multiple compilations
          make: *** [Libs/Intermediate/cliprect.o]
          Error 1
Answer: | The problem is that configure fails at detecting where X11 is installed. This means that Makefile.conf gets a faulty "-I -I" and an empty "-L". If you remove those in Makefile.conf, then your compile should preceed without problems. (Or better, modify configure to correctly locate X11, and send us a patch).

## Installing under Linux

Question: | When trying to install the ClanLib rpms I get failed dependencies...
    failed dependencies:
    libstdc++-libc6.1-1.so.2 is needed by ClanLib-...
    libm.so.6(GLIBC_2.1) is needed by ClanLib-...
    libc.so.6(GLIBC_2.0) is needed by ClanLib-...
Answer: | You don't have a new enough version of glibc. This usually happens when using the RPM's on a RedHat 5.x system, while the rpms were compiled on RH 6.0. You need to install these (or newer) RPM's: (get them from RedHat's site)
    rpm -i glib-1.2.1-2.i386.rpm
    rpm -i glibc-2.1.1-6.i386.rpm --upgrade
    rpm -i libstdc++-2.9.0-12.i386.rpm
This will enable you to use most RedHat 6.0 RPMs on the net, not just ClanLib's.

## Running under Linux

Question: | What is required to run ClanLib games under Linux ?
Answer: | ClanLib, Hermes and zlib is required to run games under Linux, unless they are statically linked to your game.

Question: | I've installed Hermes, but when I try and run any ClanLib appliction, I get errors about cannot open shared object file libHermes...
    error in loading shared libraries: libHermes.so.1: cannot open shared
    object file: No such file or directory
Answer: | Upgrade to latest Hermes (as FAQ was written this was version 1.3.x).

Question: | How can I use fullscreen with ClanLib under Linux using GGI target?
Answer: | Set the following environment variable before you start the game:
    $ export GGI_DISPLAY=dga
Note that you will have to run the game as root or setuid root for this to work.

## Compiling under Windows

Question: | I try to compile an app using ClanLib under Visual C++ and it gets unresolved external symbol _main...
    Linking...
    LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Answer: | You have to create a Win32 Application project and not a Win32 Console Application. Otherwise, add the linker option "/entry:WinMainCRTStartup" to your project options.

Question: | I try to compile an app using ClanLib under Visual C++ and it gets unresolved external symbol _WinMain...
    Linking...
    LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol
    _WinMain@16
Answer: | TODO: Link to installation guide

Question: | When I compile ClanLib, I get messages about "Directory already exists"
Question: | When I compile ClanLib, I get warnings about __NULL_IMPORT_DESCRIPTOR...
    ddraw.lib(DDRAW.dll) : warning LNK4006: __NULL_IMPORT_DESCRIPTOR already defined in winmm.lib(WINMM.dll); second definition ignored
    dsound.lib(DSOUND.dll) : warning LNK4006: __NULL_IMPORT_DESCRIPTOR already defined in winmm.lib(WINMM.dll); second definition ignored
    dinput.lib(DINPUT.dll) : warning LNK4006: __NULL_IMPORT_DESCRIPTOR already defined in winmm.lib(WINMM.dll); second definition ignored
    wsock32.lib(WSOCK32.dll) : warning LNK4006: __NULL_IMPORT_DESCRIPTOR already defined in winmm.lib(WINMM.dll); second definition ignored
Answer: | Ignore these warnings, they are non-fatal.

Question: | I get errors about conflicts with the library "LIBCMT"
    LINK : warning LNK4098: defaultlib "LIBCMT" conflicts with use of other libs; use /NODEFAULTLIB:library
Answer: | Enter the project settings, in the Link section, select the Input category, and write "libcmt" to the Ignore Libraries section.

Question: | How can I compile ClanLib under Win32 using an other compiler than Visual C++?
Question: | Can I use the windows binaries with another compiler than Visual C++?
Answer: | ClanLib does not currently officially support anything but Microsoft Visual C++ under Windows. But it should be possible to use ClanLib with other compilers. Recently support for Borland C was added, but in an experimental state. If people want to use another compiler together with ClanLib, notice that there are some things you need to be aware of: 1. You probably cannot use the win32 binaries. Because there is no standard on the symbol names used, it will be only Visual C++ 6.0 that those are guaranteed to work with. 2. You will have to make your own makefiles or projectfiles.

Question: | What is the configure app ?
Answer: | In the source package, there is a workspace called Configure.dsw. It produces the real ClanLib workspace and project files based on some questions asked in a MFC Wizard. This configure app should always be run after a ClanLib update, and of course when compiling ClanLib for the first time.

## Running under Windows

Question: | What is required to run ClanLib games under Windows?
Answer: | Nothing except your game, as all libraries will be statically linked into your game.

Question: | How do I get a console window under Windows to print debug information ?
Answer: | You can add this code to your app:
    // Create a console window for text-output if not available
    CL_ConsoleWindow console("Console");
    console.redirect_stdio();

    .... rest of app ....

    // Display console close message and wait for a key
    console.display_close_message();
Otherwise, you can specify the following linker options for a standard Win32 Application project:
    /entry:"WinMainCRTStartup" /subsystem:console

## Installing under BeOS

Question: | I'm using BeOS, where do I have to put the ClanLib libraries in order to compile anything using them - configure won't recognize their existence?
Answer: | Put them into /boot/beos/system/lib - It is not a good place for user installed libs but they are recognized there.

Question: | I can't get the BeOS port to work!
Answer: | The BeOS port is currently work-in-progress, and its not expected to work yet.

## Programming issues

Question: | I want to create a font using resource, but I get a problem when the font contains the letters ,;#{}()="
Answer: | Enclose the letters in ", and use "" to specify ". Example: ... (type=font, ..., letters="abcdef0123456,;""#{}()=");

Question: | How do I get access to the frame buffer?
Answer: | Most likely you only want access to surface data and this can be accomplished by using surface->get_provider()->get_data() after locking the provider. Don't forget to surface->reload() if you changed the data.

Question: | Are there plans to add support for Alpha blending?
Answer: | We do support alpha blending. Just load an image with alpha values, and it will alpha blend when put_screen'ed.

Question: | What happened to the Datafilecompiler since 0.3.0 ?
Answer: | The datafile compiler is now part of your executable. So if your app executable is called FooBar, your produce it like this:
    ./FooBar -datafile FooBar.scr FooBar.dat
and with Windows:
    FooBar.exe -datafile FooBar.scr FooBar.dat
If you want the makefile to build it, do something like this:
    FooBar.dat: FooBar FooBar.scr
    ./FooBar -datafile FooBar.scr FooBar.dat

    FooBar: $(OBJF)
    g++ -o FooBar $(OBJF) -lclanCore

    all: FooBar FooBar.dat
If you're using Windows, you enter the project settings menu, and add a custom build to FooBar (top tree node), and write the following:
    $(INPUTPATH) -datafile FooBar.scr FooBar.dat

Question: | What happened to the internal datafilecompiler since 0.5.0 ?
Question: | How do I compile the datafiles ?
Answer: | Please read the file README.upgrade on how to upgrade your app from earlier versions.

Question: | When I try to run my ClanLib program, it tells me there is no global CL_ClanApplication instance...
    ClanLib: No global CL_ClanApplication instance!!!
Answer: | The CL_ClanApplication class must be inherited by all ClanLib applications. In your application you must create a class inheriting CL_ClanApplication, make a global instance of it, and fill in the main() and get_title() functions.

Question: | I don't think the datafile compiler should be in our app!
Answer: | There is a technical reason that the compiler was made a part of the app: custom resources. It is possible for apps to create their own types of resources, and therefore its neccessary that the datafilecompiler is in the app.

Question: | Why is alpha blending really really slow on windows?
Answer: | The windows version of ClanLib uses DirectDraw for 2d graphics. ClanLib instructs DirectDraw per default to create the backbuffer (the screen) in video memory. Reading from video memory (which obviously is required when alpha blending) is really really slow on most graphics cards. One possible solution if you have to use a lot of alpha blending, you can try to call CL_Display::set_videomode() with the 'video_memory' flag set to false. This will create the backbuffer in system memory, which might increase performance.

Question: | I'm getting an error while using the resources. It says: Unknown type 'surface' declared for resource 'Graphics/maptiles'
Answer: | unknown type 'surface' means that you didn't initialise clanDisplay. The different resource types must be registered before trying to access the resource file, and this is done in eg. CL_SetupDisplay::init().

## CVS

Question: | I run WinCVS, and it exits with code 0...
    *****CVS exited normally with code 0******

    What do I do wrong ?
Answer: | Nothing, this simply means everything went OK.

## Misc

Question: | Where ClanLib name came from? What's the clan for?
Answer: | The Clan prefix originates from the term "The Norddahl Clan". On the old fido net, we were called this because we always shared the same opinions.

Question: | Is there a searchable archive for ClanLib mailing lists ?
Answer: | No.