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Click for my 68k-AmigaOS Ghostscript project
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GEEK SHELL RECOMMENDED FOR EXAMPLES
CLICK for: How to compile an example pthread program
Non pre-emptive POSIX threads for m68k Amiga ported, this consists of 2 gcc linker libraries libpthread.a and libpth.a.
On this webpage and its linked webpages I have created 3 of my own examples of the libpthread part of Pth. These examples have replaced the supplied examples because I understand them but dont fully understand the supplied examples. The problem with the supplied examples is I cannot tell whether or not they are malfunctioning.
To try out some examples of threaded programs using libpthread.a on 68k Amiga, visit the following pages:
CLICK for: How to compile an example pthread program with gcc
:study rhyme.c first and then you can try out windows.c which shows threads using AmigaOS intuition.library and graphics.library,
Lastly visit a mutual exclusion example, which gives a simple example of thread mutual exclusion.
Binaries have been supplied, you can run all 3 examples from AmigaOS shells provided you dont type control-C or control-D. For proper usage you should run them from a GEEK shell (currently these examples need ixemul.library):
This is a port of Ralf S Engelschall's non pre-emptive POSIX threads pth-2.0.0 In particular it includes his implementation of libpthread.a which is required for db3 which is required for rpm4. So a full port of rpm4.0 should now be possible, though I will be working on other problems first as I think a full version of rpm4.0 is a non urgent thing.
Pth-2.0.0 is a beta, libpthread appears to be functioning correctly, but may need some further changes.
This port is 2 link time libraries for gcc, libpthread.a and libpth.a, ie it is not a user level thing, nor is it OS level but is linker level.
Download the cross platform source
Download fixes to make the port happen
I attempted also to port Chris Provenzano's pre-emptive implementation of libpthread.a. But ran into a lot of problems,...
NEW DEVELOPMENTS
======== Wednesday 25th February 2004 =========
This is possibly digressing a bit, but I have decided to upload material about AmigaOS Semaphores. Almost a year ago I put a webpage about the assign count problem, but have continuously been too disorganised to upload the technique to do it properly. ok, I am addressing this problem now, better late than never!
I give a shell program that brings Semaphores to shell scripts, this is really useful eg it enables you to queue up shell scripts.
In particular it can be used to solve the assign count problem, the discussion is here
======== Monday 23rd February 2004 ============
I have created a simple example of thread mutual exclusion, complete with discussion and binary: click here for mutual exclusion example
You can run this example and the other two examples from an AmigaOS shell provided you dont type control-C or control-D. For Control-C etc you will need to run them from a Geek shell
In all the examples threads write directly to the shell, no use is made of writer threads.
My own 3 examples have now replaced the supplied examples as I dont understand the supplied ones.
======== Sunday 22nd February 2004 ============
Activity has slowed down a bit as I am trying to do too many parallel projects, further things will happen on this topic or "thread"!
I think I may wait till I have an A1 before making use of libpthread in ports. I will continue with Non-port libpthread things in the meantime. I currently wont buy an A1 until Hyperion make available this stuff
gcc is a much slower compiler than SAS Lattice C, as a result port work is very time consuming, development via SAS C 650 is much faster as a result.
================== Wednesday 11th February 2004 ===================
I have written an example threaded program showing threaded graphics. Click to download it. This example shows both traditional AmigaOS programming (intuition.library and graphics.library) and Unixy C programming and threads. Thus pthread provides a threading engine accesible to traditional AmigaOS, the only catch currently is that you need to launch the program from a Geek shell.
Its best to run it from a Geek shell, however I think you can run it from an AmigaOS shell provided you dont type control-C or D which can cause a crash. The example creates many threads, each thread opens a small window and repeatedly fills the window with different colours. All the windows appear to be rendered simultaneously, yet its non-pre-emptive threads. You can close off the windows one by one at any time. As its non pre-emptive I havent bothered with mutual exclusion, (mutual exlusion is automatic for non pre-emptive threads).
In writing this example I have located further problems, not sure if the problems are in Pth-2.0.0 or in ixemul. Anyway said problems have been carefully avoided in the example.
If you want to experiment with these pthreads then act carefully as certain things can malfunction, the innermost engine at least seems to be correctly functioning and usable.
================== Tuesday 10th February 2004 ===================
9pm: I am uploading Pth-2.0.0 as a beta, libpthread appears to be functioning correctly for a simple usage of libpthread program. For a simple usage of libpthread, explaining how to compile it, CLICK HERE!
Download the Pth-2.0.0 port (for GG)
Download the cross platform Pth-2.0.0 source
Download fixes to make the port happen
info on setting up geek shell has been updated regarding env variable HOME and PATH.
5:30pm Progress at last! I have blown several days unable to fix the problems I observed. At last I think Pth-2.0.0 is now in a usable form. I have tried to contact the Pth people by 2 different methods, but total silence. I think test_select is pathological, it would take too much time to try and decipher it, so instead I am focussing on making sure progs I write myself function.
I tried an example program from Chris Provenzano's implementation and found I have to make some slight changes to Pth-2.0.0's libpthread before CP's example happened correctly: one function of the API was missing (pthread_init()) and pthread_exit(0) was causing a recoverable alert if called by the program. These 2 problems are now fixed.
I have written a very simple example pthread program and at last this is running correctly with 68020 libpthread via Pth-2.0.0 I will generate now a 68000 default version of the linker libraries, this will take 1.5 hours to create. :you will then be able to type -lpth or -lpthread when linking. With the example the program chooses when thread rescheduling happens via pthread_yield_np(). Without this call a thread would go from start to finish without interruption (I think). I think this means you dont need mutexes but only if you use a non-pre-emptive implementation.
================== Sunday 8th February 2004 ===================
GEEK SHELL REQUIRED FOR THE EXAMPLES
As this is Unix coding I was trying everything out on the Geek shell, the idea of Geek shell + ixemul.library is to emulate the Unix environment. So I never tried it on the Amiga shell, I have now, there is malfunction via the Amiga shell eg the keyboard is frozen out of the shell for test_misc.
Therefore, you need at least a Geek Bourne shell. (pdksh is a better shell but requires more explanation to set it up). To set up a minimal Geek environment with Bourne shell, READ THIS! (updated 10feb2003)
Thus all the threaded example programs should be run from eg a Bourne or pdksh $ shell prompt.
================
I have made no further progress on the problems with pth-2.0.0, I made endless attempts to get around the problem. I have emailed Ralf Engelschall about the problems, but have been told he takes maybe 25 days to reply to emails, ==========================================================
hnl_dk noticed that pth-amiga-fixes.lha doesnt decompress properly, so this has been fixed.
I found many of the problems configuring are due to using the original Geek shell from Boot.lha, /bin/sh. Replacing this with pdksh from Geek snapshots configuring is now happening correctly. However the pth configure has semantic bugs, eg it concludes that SYS_read is not defined by gg:include/sys/syscall.h, when in fact SYS_read *is* defined there. :this bug is because SYS_read is defined by an enum and not a "#define".
I have now attempted to port pth-2.0.0 via pdksh, well it was a straight port, except I got freeze ups and other problems when I tried the supplied examples. So I fixed the SYS_read problem above, this time everything went smoothly till I tried test_sig, crash. Rebooting, I tried the examples again, this time I couldnt quit the shell.
Anyway I will try and reinstate some further things where I know the configure differs from my pth-1.4.0 configure. If I reinstate everything from my pth-1.4.0 configure then it may function correctly.
I will try to only upload pth-2.0.0 when I have it functioning reasonably,
When time permits I will upload some info on writing threaded progs
via pth and pthreads. Just the basic first steps.
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