Re: ulimit strangeness

[Peter Stephenson <pws@csr.com>]

"Bart Schaefer" wrote:
> zsh% ulimit -v $[200*1024]; limit
> cputime         unlimited
> filesize        unlimited
> datasize        unlimited
> stacksize       8MB
> coredumpsize    unlimited
> memoryuse       unlimited
> maxproc         2040
> descriptors     1024
> memorylocked    unlimited
> addressspace    200kB		<-- Note, not 200 megabytes!
>
> It looks like this has something to do with the convoluted #ifdef that
> prevents duplicate case labels in rlimits.c when both RLIMIT_RSS and
> RLIMIT_VMEM are defined, but I haven't yet figured out what to fix.

My guess is the test `RLIMIT_RSS != RLIMIT_VMEM' is incorrectly failing
in the preprocessor, i.e. it thinks RLIMIT_RSS == RLIMIT_VMEM owing to
the way the definitions are laid out.  Checking
/usr/include/sys/resource.h or carefully hidden equivalent should
confirm or refute this.  The following programme might help.

  #include <stdio.h>
  #include <sys/resource.h>

  int main(int argc, char **argv)
  {
  #if defined(RLIMIT_RSS) && defined(RLIMIT_VMEM)
      printf("You have both definitions.\n");
      if (RLIMIT_RSS == RLIMIT_VMEM)
      {
	  printf("Both have the same value.\n");
      }
      else
      {
	  printf("They have different values.\n");
  #if RLIMIT_RSS == RLIMIT_VMEM
	  printf("!!!You should never see this message!!!\n");
  #endif
      }
  #else
  #ifdef RLIMIT_RSS
      printf("You only have RSS\n");
  #else
  #ifdef RLIMIT_VMEM
      printf("You only have VMEM\n");
  #else
      printf("You have neither definition.\n");
  #endif
  #endif
  #endif

      return 0;
  }

We could probe this more reliably than at present in configure.

-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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