
DZCOMM FAQ


==========================================
============ Trivial problems ============
==========================================


   What is dzcomm?

      See readme.txt.


   Where can I get it?

      From the dzocmm homepage, 
      http://dzcomm.sourceforge.net.


   How do I use it?

      See dzcomm.txt.




========================================
============ DJGPP problems ============
========================================


   What is this make program that I'm supposed to run?

      Make is part of the standard djgpp distribution, in the file 
      v2gnu/mak*b.zip (whatever the latest version number is). You can get 
      this from http://www.delorie.com/djgpp/.


   Make doesn't work properly.

      Are you sure that you have installed djgpp correctly? Check the 
      instructions in the djgpp readme.1st file, and in particular confirm 
      that you have set the DJGPP environment variable and added the 
      djgpp\bin directory to your path.


   My djgpp installation is fine, but make still doesn't work properly.

      Are you sure that you are using the GNU make program, and not some 
      other version like the Borland one? If in doubt, run "make -v" and 
      check that the GNU copyright message is displayed.


   When I run make, it asks me for some parameters. What do I type?

      You shouldn't be running make from the Win95 explorer! Bring up a DOS 
      box, change to your Allegro directory, and type "make" at the command 
      prompt.


   When I run make, it says "makefile has modification time in the future".

      Are you sure that your system time and date are set correctly?


   When I run make, it says "virtual memory exhausted".

      As the error message suggests, you need to provide more memory for the 
      compiler to use. The go32-v2 program will tell you how much is 
      currently available. If you are running under DOS, try to free up more 
      disk space for use as a swapfile. When using win95, increase the DPMI 
      memory limit in the properties for your DOS session to 65535 (you'll 
      have to type this in by hand, because the pulldown list doesn't go 
      above 16384).


   make says "reloc refers to symbol 'bss' which is not being output".

      This seems to be a problem with the replacement linker from the 
      RSXNTDJ package. Either go back to using the standard djgpp linker, or 
      remove the "-s" flag from the Allegro makefile. If anyone knows why 
      this happens, and how I can avoid it, I'd like to know about it!


   When I try to compile a program using Allegro, I get lots of errors like:
   C:\TEMP\ccdaaaaa(.text+0x9):x.c: undefined reference to `allegro_init'
   C:\TEMP\ccdaaaaa(.text+0xe):x.c: undefined reference to `install_keyboard'

      You haven't read the docs, have you? :-) You need to link your program 
      with the library file, liballeg.a. First, make sure you have installed 
      everything properly (running make should do this for you). Second, if 
      you are compiling from the command prompt or with a makefile, add 
      -lalleg to the end of your gcc command line, or if you are using 
      Rhide, go to the Options/Libraries menu, type 'alleg' into the first 
      empty field, and make sure the box next to it is checked.


   I give up: I can't compile this! Can you send me a precompiled version?

      No, sorry. For starters, liballeg.a is about 450k, but you'd probably 
      also want  various utilities like the grabber, sound setup, etc. And 
      what about all the example programs? If I included compiled versions 
      of everything, a binary distribution would be over 7 megs: way too big 
      to be practical! More seriously though, there just isn't any reason 
      why you can't build it yourself. A compiler is a deterministic 
      process: given a particular input file and command line, it will 
      always produce the same output. If this isn't working, you either have 
      the wrong input files (ie. your copy of Allegro is broken in some 
      way), or the wrong command line (it is hard to see how that could 
      happen, since all you have to do is type "make"...) or your compiler 
      is broken, ie. you didn't install djgpp properly. You need to find and 
      fix the problem, not just sweep it under the carpet by getting someone 
      else to compile Allegro for you...




======================================
============ DOS problems ============
======================================


   Does the DOS version of Allegro work under Windows NT?

      Your mileage may vary. Some people have reported problems, while 
      others say that it works fine. I don't have access to NT myself, so 
      there is nothing I can do about it either way, and to be honest I 
      don't care very much. Use the Windows version of Allegro if you want 
      to make Windows programs. If you want to run DOS programs, use DOS!


   Does Allegro work under OpenDOS?

      Yes, but with some caveats. If you are using the OpenDOS version of 
      EMM386, you must disable their DPMI implementation (specify DPMI=OFF 
      on the EMM386.EXE device line in your config.sys). You should also 
      make sure the PIC=OFF flag is set, but this is the default so it won't 
      be a problem unless you have specifically enabled it.


   How can I extend the 256k limit on Mode-X video memory?
   I have two megs in my card.

      You can't. The limit is imposed by the VGA hardware, not by Allegro. 
      To access more than 256k of video memory you need to use an SVGA mode, 
      which means either switching to a higher resolution or getting a copy 
      of the SciTech Display Doctor, which provides several low resolution
      SVGA modes.


   Does DOS Allegro work with the SB-Live soundcard?

      It does for some people, but not for others. The problem is that 
      Creative Labs refuse to release any specs, so we don't know how to 
      write a driver for it. Complain to them, or buy a different card from 
      a more reasonable manufacturer.


   Why does DOS Allegro play sounds so much quieter than in Windows?

      This might be because you have the volume set very low: try changing 
      this in the setup program. Also, Allegro is mixing several sounds into 
      a single output buffer, unlike the Windows sound player that only 
      plays one sample at a time, so each individual sound can only get a 
      smaller percentage of the total output volume. This is just the price 
      you pay for multiple output channels. If you don't like it, use the 
      setup program to tweak the number of channels: this can be any power 
      of two less than or equal to 64, and the smaller you make it, the 
      louder the sound will be.


   Why doesn't it work with my video card?

      Try using a FreeBE/AF driver (http://www.talula.demon.co.uk/freebe/),
      or the commercial SciTech Display Doctor (http://www.scitechsoft.com).
      If it still doesn't work, post a description of your problem to the 
      Allegro mailing list, along with a copy of the output from running the 
      afinfo and vesainfo programs.


   Why not use some sort of dynamic linking system?

      The VBE/AF interface already provides this for the video drivers: see 
      the FreeBE/AF project on http://www.talula.demon.co.uk/freebe/.
      For more general things like the sound, VESA, and mode-X routines, 
      this would be very difficult to do because the drivers depend on a lot 
      of helper functions from the core lib. The djgpp DXE format is nowhere 
      near flexible enough to support this, and I don't want to make Allegro 
      dependent on any other dynamic linking packages.




==========================================
============ General problems ============
==========================================



   Can I use dzcomm with my <foobar> compiler?

      Not unless <foobar> is mentioned in readme.txt as one of the 
      supported platforms. You could port it, but that is usually a lot of 
      work. If <foobar> is a 16 bit DOS compiler like Borland C, you 
      might as well just forget the idea :-)


   What is this "WIP" that I see people talking about?

      WIP stands for "work in progress", and refers to any changes that are 
      more recent than the last official release. WIP versions of the 
      library can be obtained as from the dzcomm website 
      (http://www.robots.ox.ac.uk/allegro/dzcomm), and are usually 
      quite stable, although obviously not so well tested as a final release 
      version.

   Why aren't there more answers in this file?

      Not enough people have asked me questions often enough. Either it's all
      obvious or everyone's given up.


   Can I use dzcomm in my <whatever> commercial application?

      Sure. See the giftware terms in readme.txt. I don't mind what you do 
      with it, and there are no problems with commercial usage.


   When will <foobar> be finished? I can't wait...

      Whenever it is done! A little encouragement is always welcome, but I 
      don't have any completion deadlines and I'm not going to make one up 
      for you :-) As soon as it is finished, it will be released.


   How can I print out the documentation?

      The dzcomm.rtf file can be read directly into Microsoft Word and 
      printed from there, but you should right-click and update the table of 
      contents and index fields to fill them with the correct data first. 
      Alternatively you can install the TeX package and use the tex and 
      dvips programs to convert allegro.txi into Postscript format.


   I'm still confused. Where can I get help?

      Mail neil@robots.ox.ac.uk.


