C example of storage management

Following is an example of how to manage storage for a C program using callable services.

/*Module/File Name: EDCSTOR                                     */
/****************************************************************/
/*                                                              */
/* Function   : CEE3RPH - Set report heading                    */
/*            : CEECRHP - Create user heap                      */
/*            : CEEGTST - Obtain storage from user heap         */
/*            : CEECZST - Change size of this piece of storage  */
/*            : CEEFRST - Free this piece of storage            */
/*            : CEEDSHP - Discard user heap                     */
/*                                                              */
/*    This example illustrates the invocation of the Language   */
/*    Environment Dynamic Storage Callable Services for a       */
/*    C program                                                 */
/*    1.  A report heading is set for display at the beginning  */
/*        of the storage or options report.                     */
/*                                                              */
/*    2.  A user heap is created.                               */
/*                                                              */
/*    3.  Storage is allocated from the user heap.              */
/*                                                              */
/*    4.  A change is made to the size of the allocated storage.*/
/*                                                              */
/*    5.  The allocated storage is freed.                       */
/*                                                              */
/*    6.  The user heap is discarded.                           */
/*                                                              */
/*****************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <leawi.h>
#include <ceeedcct.h>
void main ()
{
  _CHAR80 RPTHEAD;
  _INT4 HEAPID;
  _INT4 HPSIZE;
  _INT4 NBYTES;
  _INT4 INCR;
  _INT4 OPTS;
  _INT4 STORALC;
  _POINTER ADDRSS;
  _FEEDBACK FC;
  printf ( "\n**********************************\n");
  printf ( "\nCE90STO C Example is now in motion\n");
  printf ( "\n**********************************\n");
  memset ( RPTHEAD , ' ' , 80 );
  memcpy ( RPTHEAD , "User defined report heading" , 27 );
  /*******************************************************
   * Call CEE3RPH to set the user defined report heading *
   *******************************************************/
  CEE3RPH ( RPTHEAD , &FC );
  if ( _FBCHECK ( FC , CEE000 ) != 0 )
      printf ( "Error in setting report heading\n" );
  /*******************************************************
   * Call CEECRHP to create a user heap                  *
   *******************************************************/
  HEAPID = 0;
  HPSIZE = 1;
  INCR = 0;
  OPTS = 0;
  STORALC = 0;
  CEECRHP ( &HEAPID , &HPSIZE , &INCR , &OPTS , &FC );
  if ( _FBCHECK ( FC , CEE000 ) == 0 )
    {
    /*******************************************************
     * Call CEEGTST to get storage from user heap          *
     *******************************************************/
    NBYTES = 4000;
    CEEGTST ( &HEAPID , &NBYTES , &ADDRSS , &FC );
    if ( ( _FBCHECK ( FC , CEE000 ) == 0 ) && ADDRSS != 0 )
      {
      /*******************************************************
       * Call CEECZST to change size of heap element         *
       *******************************************************/
      NBYTES = 2000;
      CEECZST ( &ADDRSS , &NBYTES , &FC );
      if ( _FBCHECK ( FC , CEE000 ) == 0 )
        {
          STORALC = 1;
        }else{
          printf ( "Error in changing size of storage\n");
      }
      }else{
        printf ( "Error in getting user storage\n" );
    }
    }else{
      printf ( "Error in creating user heap\n" );
  }
 if (STORALC != 0)
  {
  /*******************************************************
   * Call CEEFRST to free this piece of storage          *
   *******************************************************/
  CEEFRST ( &ADDRSS , &FC );

  if ( _FBCHECK ( FC , CEE000 ) == 0 )
    {
    /*******************************************************
     * Call CEEDSHP to discard user heap                   *
     *******************************************************/
     CEEDSHP ( &HEAPID , &FC );
     if ( _FBCHECK ( FC , CEE000 ) == 0 )
       {
         printf ( "C/370 Storage Example ended\n" );
         exit(0);
       }else{
         printf ( "Error discarding user heap\n" );
     }
     }else{
       printf ( "Error freeing storage from heap\n" );
    }
  }
  exit(-1);
}