[fpc-pascal] FPC 2.6.2 for DOS/Go32V2 FP.EXE cannot run a second time

[Tomas Hajny]

On Tue, September 17, 2013 20:57, Lubomír Čabla wrote:
> FPC 2.6.2 for DOS/Go32V2
>
> There is the fatal IDE unstability in FPC 2.6.2 under pure DOS.
>
> IDE almost always starts only first time (after installation or reboot).
> I start the IDE, compile and run the program (e.g. Hello.pas) and close
> IDE. But when I want to start IDE again it crashes with SIGSEGV message.
>
>  Exiting due to signal SIGSEGV
>  FPC General Protection Fault at eip=006EDE95
>  eax=65672D6C ebx=0000002A ecx=00000088 edx=00000000 esi=008E91F8
> edi=0083B504
>  ebp=008C0CA0 esp=008C0C90 program=C:\PP\BIN\GO32V2\FP.EXE
>  cs: sel=00A7 base=00400000 limit=008EFFFF
>  ds: sel=00AF base=00400000 limit=008EFFFF
>  es: sel=00AF base=00400000 limit=008EFFFF
>  fs: sel=00C7 base=00000000 limit=0010FFFF
>  gs: sel=00C7 base=00000000 limit=0010FFFF
>  ss: sel=00AF base=00400000 limit=008EFFFF
>
>  Call frame traceback EIPs:
>  $006EDE95
>  $005BD905
>  $005BCD84
>  $005BC83D
>  $005BC7F8
>  $00308AF8
>  $0030B9F4
>  $0002DB50
>  $0002DC5A
>  $00002040
>
> To be able to start IDE again in DOS I have to reboot the computer.
> I think IDE set something in memory and warm restart does not erase the
> memory contents.
>
> Compilation from command prompt with FPC.EXE works everywhere.
> But IDE is good for debugging and help.
>
> Can someone please help me or advise what I'm doing wrong.
>
> The main problem is running IDE in pure DOS.

Which DOS version is it? Is there any DPMI provider running before
starting the IDE (some DOS versions include DPMI host themselves)?

If there is no other DPMI host (running) and thus CWSDPMI.EXE is used, I'd
recommend starting with a check whether there is just one (the latest)
CWSDPMI.EXE and just for test purposes try loading it into memory as TSR
with options "-p -x" (see cwsdpmi.txt included in directory doc\fpc) to
see if it makes any difference.

Obviously, the next step would be compiling the IDE with debug information
(including -gl) to see where exactly it fails.

Tomas