From:	"Michael Allison" <michael DOT allison2 AT sympatico DOT ca>
Newsgroups:	comp.os.msdos.djgpp
References:	<wkbm6.226404$Pm2 DOT 3670275 AT news20 DOT bellglobal DOT com> <CScm6.227001$Pm2 DOT 3684848 AT news20 DOT bellglobal DOT com>
Subject:	Re: Eradicating djgpp W2000 problem
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Date:	Sun, 25 Feb 2001 19:30:56 GMT
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Organization:	Sympatico
To:	djgpp AT delorie DOT com
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Reply-To:	djgpp AT delorie DOT com

"Michael Allison" <michael DOT allison2 AT sympatico DOT ca> wrote in message
news:CScm6.227001$Pm2 DOT 3684848 AT news20 DOT bellglobal DOT com...
> "Michael Allison" <michael DOT allison2 AT sympatico DOT ca> wrote in message
> news:wkbm6.226404$Pm2 DOT 3670275 AT news20 DOT bellglobal DOT com...
> >
> > Let's constructively try to come up with the absolute minimum set
> > of two programs that can cause the problem to occur, as a start
> > to understanding it.
>
> There is obviously more to reproducing this problem than
> nesting djgpp programs as people claim.  The code below
> went to 6 levels of nesting fine on Windows 2000 professional.

If I change execute_by_shell to zero in the code below
I get a "Load error: no DOS memory" after 37 levels of
nesting djgpp programs, which isn't too surprising.

When I set execute_by_shell to 1 I get 35 levels of
nesting with any shell with no error message generated.


/* djgpp toplevel test program for isolating
   Windows 2000 problem. parent.c */
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <process.h>

char *default_shell = "command.com";
static int execute_by_shell;
int dos_status;
int proc_return;
int nesting_level = 0;

#define CMDBUFSIZ 200
char *parentenv[] =
{
   "PARENT1=environment will be",
   "PARENT2=passed to child process",
   (char *)0
};

char nestval[CMDBUFSIZ];

char *args[] = {
   "parent.exe",
   nestval,
   (char *)0
};


int main(int argc, char *argv[])
{
    char mycmdline[CMDBUFSIZ];
    execute_by_shell = 0;

    if (argc > 1)
 nesting_level = atoi(argv[1]);
    nesting_level++;
    if (nesting_level > 300) return 0;
    (void) itoa(nesting_level, nestval, 10);

    printf("\nIn child, nesting level %s (by %s)\n",
 nestval,
 execute_by_shell ? default_shell : "spawnvpe");

    if (execute_by_shell) {
 char *cmdline = mycmdline;
 (void) strncpy(mycmdline, argv[0],
  CMDBUFSIZ - (sizeof(nesting_level) + 1));
 (void) strcat(mycmdline, " ");
 (void) strcat(mycmdline, nestval);
 proc_return = system (cmdline);
    } else {
 proc_return = spawnvpe (P_WAIT, args[0],
   args, parentenv);
    }
    /* If the child got a signal, dos_status has its
       high 8 bits set, so be careful not to alter them.  */
    if (proc_return == -1)
 dos_status |= 0xff;
    else
 dos_status |= (proc_return & 0xff);
    return dos_status;
}

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