NetNews Usenet Archive 1993 #1

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Path: sparky!uunet!munnari.oz.au!comp.vuw.ac.nz!actrix!templar!jbickers From: jbickers@templar.actrix.gen.nz (John Bickers) Newsgroups: comp.sys.amiga.programmer Subject: FAQ (long). Message-ID: <jbickers.0n2z@templar.actrix.gen.nz> Date: 12 Jan 93 20:43:26 PST Organization: TAP Lines: 491 Well, I couldn't make a fortnightly schedule, so this is now monthly. I've rearranged the layout a bit. We also had a news blackout here last week. ------------------------------ 8< ------------------------------ Last modified 12th Jan 1993. Please address feedback to: jbickers@templar.actrix.gen.nz. TABLE OF CONTENTS 1 MAILING LISTS 2 LIBRARIES 3 AVAILABLE COMPILERS & TOOLS 4 COMMUNICATIONS INFORMATION 4.1 Dropping DTR. 5 DOS INFORMATION 5.1 Can an ACTION_READ to a console be aborted? 5.2 Need a pointer to a CLI window. 5.3 Checksum errors, trimnews and hard links. 5.4 Scanning each entry in a multi-assign. 5.5 Read character from console immediately (raw). 5.6 How the Amiga FS works. 6 EXEC INFORMATION 6.1 What do GURU numbers mean? 6.2 How do you debug an input handler / task? 7 GRAPHICS INFORMATION 7.1 What is DIG/RTG? 7.2 What is the format of IFF ILBM and ANIM files? 8 INTUITION INFORMATION 8.1 How do I block a window from user input? 8.2 Some Workbench icons disappear during WindowToBack()! 9 SAS C INFORMATION 9.1 Are malloc()/free() much slower under 6.1 than 5.10? 9.2 How do I get rid of the CON: created from Workbench? *** 1 MAILING LISTS A number of mailing lists are set up for email discussion of specific subjects. These include: a68k-request@castrov.cuc.ab.ca Discussion of Charlie Gibb's A68k freeware assembler. amigalisp-request@contessa.palo-alto.ca.us Discussion of LISP, Scheme, ML, Gofer, functional programming, and other such things. dice-request@castrov.cuc.ab.ca Discussion of Matt Dillon's shareware DICE C compiler. xpr-request@aldhfn.akron.oh.us Discussion of the XPR file transfer protocol. *** 2 LIBRARIES iff.library [Christian Weber] Routines to read and write IFF files, with direct support for ILBM and ANIM forms for pictures and animations. ANIM support includes decoding of DLTA chunks. It is also XPK-aware. It is available from amiga.physik.unizh.ch and on Fish disk #674. pattern.library [Angela Schmidt] AmigaDOS pattern matching routines which are less buggy than OS (KS2.0) or ARP (KS1.2) routines, and include some special- case optimizations. It is available from ftp.wustl.edu and on Fish disk #625. reqtools.library [Nico Franτois] String, screen, color, file and font requesters, with a 2.0 look. It is available from amiga.physik.unizh.ch. xpkmaster.library [Dominik Mueller et al] A variety of data compression and encryption routines managed through a set of sublibraries. Can compress RAM to RAM, file to RAM, RAM to file, etc. The user and development archives are available from amiga.physik.unizh.ch. xpr<proto>.library [Willy Langeveld et al] A variety of external protocol libraries that meet the XPR 2.0 specification. The spec. can be found on Fish disk #247. The libraries themselves are often distributed independently. Join the XPR mailing list for information about XPR 3.0. *** 3 AVAILABLE COMPILERS & TOOLS a68k Charlie Gibbs' freeware 680x0 assember, available from amiga.physik.unizh.ch. AdaEd An Ada implementation, available from wuarchive.wustl.edu as programming/programming/ada/adaed-1.0.11a.lzh. ARexx William Hawes' commercial REXX package. The address is: Post.: Wishful Thinking Development Corp., PO Box 308, Maynard, MA 01754, USA. Voice: +1-508-568-8695 Comeau C++ 3.0 With Templates Comeau Computing's commercial C++ package. Their address is: Email: attmail.com!csanta!comeau Post.: Comeau Computing, 91-34 120th Street, Richmond Hill, NY 11418, USA. Voice: +1-718-945-0009 / Fax: +1-718-441-2310. DICE Matt Dillon's shareware C compiler, available from amiga.physik.unizh.ch. His address is: Email: dillon@overload.berkeley.ca.us Post.: Matthew Dillon, 1005 Apollo Way, Incline Village, NV 89451, USA. Gofer See the LISP entry for more information. GNU C Markus Wild's port of this freeware C compiler, available from amiga.physik.unizh.ch. LISP Several implementations are available from gatekeeper.pa.dec. com, in the directory /pub/micro/amiga/lisp. The file LISP.LIST has pointers to other sources. An up-to-date version of this is available via BMS from contessa.palo-alto.ca.us as bms:pub/lisp.list. See the Amiga LISP mailing list for more information. ML See the LISP entry for more information. PCQ Pascal Patrick Quaid's freeware Pascal compiler, available from amiga.physik.unizh.ch. Scheme Suitable Schemes for use with Abelson & Sussman's "Structure and Interpretation of Computer Programs" are SIOD, Ed Turner's Scheme, or XScheme. If you have experience to the contrary, please let amigalisp@contessa.palo-alto.ca.us and the FAQ list maintainer know. These systems are available at gatekeeper.pa. dec.com, in /pub/micro/amiga/lisp. SIOD is also on Fish disk #525, and Scheme is on disk #149. See the LISP entry for more information. *** 4 COMMUNICATIONS INFORMATION 4.1 Dropping DTR. a. If you are using a CBM device, eg serial.device, you must call CloseDevice() to drop DTR. DTR is asserted when you open the device, and no other system mechanism is provided to drop it. Be aware that this fails if another application has opened the device in SHARED mode. b. Many other devices support an extra command to control the DTR and RTS lines. This was originated by ASDG. The following is extracted from code originally posted by Russell McOrmond: #define SIOCMD_SETCTRLLINES 0x10 #define SIOB_RTSB 0 #define SIOB_DTRB 1 #define SIOB_RTSF (1<<SIOB_RTSB) #define SIOB_DTRF (1<<SIOB_DTRB) IOSer.io_Command = SIOCMD_SETCTRLLINES; IOSer.io_Offset = SIOB_DTRF; if (raising DTR) IOSer.io_Length = SIOB_DTRF; else IOSer.io_Length = 0; The io_Offset is a mask of bits to be affected (RTS and DTR), and the io_Length is a value to set each bit to. So to drop DTR you set the DTR bit in io_Offset, and clear the DTR bit in io_Length. To raise DTR again, you set the DTR bit in both io_Offset and io_Length. c. If you are using the internal serial port with CBM's serial.device, you can drop DTR without calling CloseDevice by banging the hardware. Again the following is extracted from code originally posted by Russell McOrmond: struct CIA *Ciab = (struct CIA *)0xbfd000; Disable(); Ciab->ciaddra |= CIAF_COMDTR; /* Set DTR as output */ if (raising DTR) Ciab->ciapra &= ~CIAF_COMDTR; /* Raise */ else Ciab->ciapra |= CIAF_COMDTR; /* Drop */ Enable(); *** 5 DOS INFORMATION 5.1 Can an ACTION_READ to a console be aborted? No, with the exception that if you close the console, then all pending packets are returned. 5.2 Need a pointer to a CLI window. a. The following may return a pointer with a value of -1, if the console you were launched from has had requesters disabled. struct Process *pProc; pProc = (struct Process *)FindTask(NULL); pWin = pProc->pr_WindowPtr; b. The following code is SAS C specific, but should be easy to modify for other compilers: /* findwindow.c - utility routine to find window of a CLI. From: deven@rpi.edu (Deven T. Corzine) Subject: Re: Finding Windows Date: 20 Jul 90 16:14:05 GMT */ #include <exec/types.h> #include <exec/memory.h> #include <proto/exec.h> #include <proto/dos.h> struct Window __regargs *FindWindow() { register struct DosLibrary *DOSBase; register struct Window *win; register struct Process *proc; register struct CommandLineInterface *cli; register struct InfoData *id; register struct StandardPacket *pkt; register struct FileHandle *fh; register BPTR file; register long ret1,ret2; if (DOSBase=(struct DosLibrary *) OpenLibrary(DOSNAME,0)) { if (id=(struct InfoData *) AllocMem(sizeof(struct InfoData),MEMF_PUBLIC|MEMF_CLEAR)) { if (pkt=(struct StandardPacket *) AllocMem(sizeof(struct StandardPacket),MEMF_PUBLIC|MEMF_CLEAR)) { proc=(struct Process *) FindTask(NULL); if (cli=(struct CommandLineInterface *) (proc->pr_CLI<<2)) { ret1=cli->cli_ReturnCode; ret2=cli->cli_Result2; if (file=Open("*",MODE_NEWFILE)) { if (IsInteractive(file)) { pkt->sp_Msg.mn_Node.ln_Name=(char *) &(pkt->sp_Pkt); pkt->sp_Pkt.dp_Link=&(pkt->sp_Msg); pkt->sp_Pkt.dp_Port=&(proc->pr_MsgPort); pkt->sp_Pkt.dp_Type=ACTION_DISK_INFO; pkt->sp_Pkt.dp_Arg1=((ULONG) id)>>2; fh=(struct FileHandle *) (file<<2); PutMsg(fh->fh_Type,(struct Message *) pkt); WaitPort(&(proc->pr_MsgPort)); GetMsg(&(proc->pr_MsgPort)); win=(struct Window *) id->id_VolumeNode; } Close(file); } cli->cli_Result2=ret2; cli->cli_ReturnCode=ret1; } FreeMem(pkt,sizeof(struct StandardPacket)); } FreeMem(id,sizeof(struct InfoData)); } CloseLibrary((struct Library *) DOSBase); } return(win); } 5.3 Checksum errors, trimnews and hard links. [Randell Jesup] The filesystem has a problem with deleting the target of a hardlink, especially on dir-cached partitions (DOS\5), but also hardlinked directories on FFS, and on files and directories under OFS (though you may not see the problem unless you need to recover the partition). Temporary solutions: don't use hardlinks to directories, and don't put UUCP news on DCFS partitions. This will be fixed in a future release of the FS. 5.4 Scanning each entry in a multi-assign. [Randell Jesup] BOOL do_something_to_all(char *path, BOOL (*function)(BPTR lock)) { struct DeviceProc *dp = NULL; struct MsgPort *old_fsport; BPTR lock, old_curdir; char *remainder; LONG err; // NOTE: not strrchr - PathMan has files with ':'s in them remainder = strchr(path,':'); if (remainder == NULL) remainder = path; else remainder++; /* point past ':' */ while (1) { dp = GetDeviceProc(path,dp); if (!dp) { /* getdevproc freed dp for us */ // NOTE: 2.04 and 3.0 have a bug, and never return // ERROR_NO_MORE_ENTRIES. Accept 0 as no error as well // This will be fixed next release. err = IoErr(); if (err == 0 || err == ERROR_NO_MORE_ENTRIES) return TRUE; // all done else return FALSE; // never found anything } /* save filesystem port pointer, set default FS to target */ old_fsport = SetFileSysTask(dp->dvp_Port); old_curdir = CurrentDir(dp->dvp_Lock); // may be NULL /* we have an entry, get a lock on the remainder of path */ lock = Lock(remainder,SHARED_LOCK); /* reset filesystem port and current dir */ (void) SetFileSysTask(old_fsport); (void) CurrentDir(old_curdir); /* we got a lock on it, call user function. Function can */ /* return FALSE to stop the scan. */ if (!lock || !(*function)(lock)) { UnLock(lock); // NULL is safe FreeDeviceProc(dp); return FALSE; } UnLock(lock); } } Warning: that was written off the top of my head, but I do have the source code for reference. Also, at least one developer has used this and it works. 5.5 Read character from console immediately (raw). It is often useful to have functions like getchar() return immediately when the user presses a key, rather than waiting until they hit Enter. To do this, you need to switch your console into "raw" mode. The line-based mode is referred to as "cooked" mode. a. Under KS2.0, dos.library has a function SetMode() that does it all. b. Under DICE, the link library function setvbuf() also switches modes automatically. c. Otherwise, you need to send an ACTION_SCREEN_MODE packet to the console yourself. Set arg[0] to -1L for raw mode, 0 for cooked mode. 5.6 How the Amiga FS works. [Randell Jesup, on coroutines in Amiga filesystems] Yes, they're coroutines (BCPL ones). Anything that blocks in exec (i.e. Wait()) will stop all of them. Internally, it switches around between them as needed (no preemption). CallCo() will swap to a coroutine (much like jsr), WaitCo() returns a results to the parent (much like rts). One important difference with subroutines is that the coroutines maintain their own stacks and state. ResumeCo() is basically a branch to a coroutine (as if it had been CallCo'd by your caller - much like exiting a subroutine with jmp some_other_subrutine). There are various other utility functions, like StartCo, KillCo, CreateCo, etc. Each open filehandle is a coroutine. The master coroutine CallCo()'s it when it gets a packet or when IO comes back. Note that this is where the stack-based state information of the coroutine come into play - a filehandle coroutine does IO by queuing a request, and calling WaitCo(). The disk read/write coroutine pulls things from the queue and gets woken up when IO is done. When an IO is complete and verified, it notes which coroutine is waiting for the IO to complete (can be a list), and ResumeCo()'s that coroutine. Since the coroutine has a stack, it continues at the point after the WaitCo with whatever it was doing, now knowing the IO was complete. Note that the master coroutine doesn't CallCo() an active filehandle coroutine, it queues the packet for later handling. If this seems simple, I guarantee you, IT'S NOT. It's mind-warping and arcane when you need to care about the coroutines (but easy and straightforward when you don't). A lot of state information becomes automatic, without having to build a (massive) explicit state machine. I burnt out a lot of brain cells figuring out how to handle locking of updates to hash chains in this setup, since this required major interactions between coroutines. The end result was simple, but it was a bitch to figure out. *** 6 EXEC INFORMATION 6.1 What do GURU numbers mean? Get Stegan Zeiger's program "alert" from amiga.physik.unizh.ch or Fish disk #636. It will translate the 32-bit GURU values into something more understandable. 6.2 How do you debug an input handler / task? a. Create a message port in the parent process to which you can send messages from the handler. b. Use the kprintf() routines in debug.lib, optionally trapping the output to a console with Sushi. *** 7 GRAPHICS INFORMATION 7.1 What is DIG/RTG? DIG is Device Independent Graphics. A set of graphics routines that does not require a particular device to work. RTG is ReTargetable Graphics. A set of graphics routines that normally work with a particular device, but can be changed at a low level to work with other devices. They are basically the same thing, though DIG is more often used to refer to things like Postscript where the output device can be a monitor, a plotter, a printer, etc. RTG is more often used to refer to different display hardware, usually meaning a different number of colors or a different pixel format, planar vs chunky. 7.2 What is the format of IFF ILBM and ANIM files? The complete format specs for these files can be found on Fish disk #185. That disk also includes public domain code for the creation of OPT 5 DLTA chunks for ANIM files. It may not be necessary to know the exact format if you use a library such as iff.library for loading and saving pictures. This library also contains a routine for decoding DLTA chunks from ANIM files, including OPT J chunks from the old Sculpt 3D movies. OPT J chunks used to be proprietary. *** 8 INTUITION INFORMATION 8.1 How do I block a window from user input? Normally this is required when you want to open a second window that should act like a requester. The solution is to open a real requester in the window you want to block, that is 1 pixel by 1 pixel, and hidden somewhere in your first window. Remove this tiny requester when you are ready to close your "requester". You can also change the IDCMP flags on your first window so that messages don't pile up. 8.2 Some Workbench icons disappear during WindowToBack()! [Markus Juhani Aalto] You have to try to lock layers before using WindowToBack(). /* Lock layers. If someone else has locked it, then we wait. */ LockLayerRom( WorkbenchScreen->LayerInfo.top_layer ); Forbid(); UnlockLayerRom( WorkbenchScreen->LayerInfo.top_layer ); WindowToBack(MyWindow); /* Or WindowToFront() */ Permit(); *** 9 SAS C PROBLEMS 9.1 Are malloc()/free() much slower under 6.1 than 5.10? Performance problems in programs with a lot of small malloc()/ free() calls may be overcome by reducing the page size used by the memory management code. This is done by declaring a global constant: unsigned long _MSTEP = <whatever>; 9.2 How do I get rid of the CON: created from Workbench? The window is opened by the ___main() function. Refer to Appendix 1 of the SAS C User's Guide, Volume 1. -- *** John Bickers, TAP. jbickers@templar.actrix.gen.nz *** *** "Radioactivity - It's in the air, for you and me" - Kraftwerk ***