/*************************************************
 * Grab some shared memory.
 * This program was written to test how much can
 * shared memory we can get out of an HP-UX 10.20.
 *
 * Whatch out, you need to release the memory using
 * ipcrm !
 *
 * Everytime you'll run this prg, it will grab a new
 * piece of memory. THIS PROGRAM DOES NOT RELEASE
 * SHARED MEMORY !!!
 *
 *
 *
 * Copyright Yves Dorfsman 1999.
 *************************************************/




#include <stdio.h>
#include <stdarg.h>
#include <sys/shm.h>
#include <sys/ipc.h>
#include <errno.h>
#include <string.h>
#include <strings.h>




void usage(char*);




main(int argc, char** argv)
{
int    howlong, shm_id;
char   num[255], *unit;
long   size;


if (argc != 2)
  {
  usage(argv[0]);
  return -1;
  }


/***************
 * If the arg finishes with m, M, k, or K, then the size is in MegaBytes,
 * or KiloBytes.
 * We need to split the arg in two pieces: the last character (unit)
 * and the rest (num).
 * eg: argv[1]=22M  ==> num=22, unit=M
 ****************/
howlong = strlen(argv[1]) - 1;
strncpy(num, argv[1], howlong);
unit = argv[1] + howlong;
printf("%s  %s\n", num, unit);


/***********
 * Ok, now that we have num and unit, we have to find out if unit
 * is a number (in which case the arg was given in bytes and is equal
 * to argv[1]), a k (then, arg is in kbytes), etc...
 ***********/
/* We assume that unit = k */
size = atol(num) * 1024;

if ( strcasecmp(unit, "m") == 0)
  size *= 1024;
else  if ( strcasecmp(unit, "g") == 0)
        size *= 1048576;
      else  if ( strcasecmp(unit, "k") != 0)
              /* if neither gig nor meg nor kilo, then was all number */
              size = atol(argv[1]);

printf("\nGetting a shared memory segment of %d\n", size);
shm_id = shmget(0, size, 0666);

if (shm_id == -1)
  {
  perror(argv[0]);
  return errno;
  }
else
  {
  printf("Shared memory ID = %d\n", shm_id);
  printf("Please remember to release it with ipcrm.\n\n");
  }


}








void usage(char* progname)
{
fprintf(stderr, "\n\t%s:\tSyntax error.\n", progname);
fprintf(stderr, "\tUsage:\t%s size\n\n", progname);
fprintf(stderr, "\tsize can be express in bytes, KB, MB, or GB.");
fprintf(stderr, "\tSimply add the suffix k,m, or g imediately after the number");
fprintf(stderr, "\tUsage:\t%s 100m\n\n", progname);
}