/* Gamelon(tm) File I/O Library Sample Code C Language */
/* (C)1994 Menai Corporation(tm) Released for public use */
/* Example 2a. How to put a series of objects into an */
/* empty aggregate using the PreFirst position. */
/* The PreFirst position is defined to be prior to */
/* the first object within the immediately enclosing */
/* aggregate. If the aggregate is empty, PreFirst is */
/* defined to be prior to any potential position of */
/* objects contained within the aggregate. PreFirst */
/* is shown graphically as: */
/* { } */
/* < */
/* Normally, PreFirst is only shown when one or more */
/* Cursors are actually in the PreFirst position. */
/* When in the PreFirst position, a cursor may only */
/* append objects after its current position. Insert, */
/* Replace, Remove and Modify alterations are not */
/* possible from the PreFirst position. The following */
/* API calls may be used to add a series of data */
/* objects from the PreFirst position (assume an */
/* empty file): */
#include <stdlib.h>
#include "gfcursor.h"
int main(void) {
short i = 2;
char ch = 'b';
double db = 3.14159;
int valid;
CURSOR *c = new_CURSOR(NULL,
"newfile",
AM_SHARED,
NULL,
0);
eCursorQueryValid(c, &valid);
if (!valid)
exit(1);
eCursorMoveIn(c);
/* Since aggregate is empty, Cursor moves to the */
/* Null position. Cursor must move to PreFirst or */
/* PostLast in order to make alterations.
*/eCursorMovePreFirst(c);
eAltAppend(c);
eObjWriteShort(c, i);
eAltAppend(c);
eObjWriteChar(c, ch);
eAltAppend(c);
eObjWriteDouble(c, db);
delete_CURSOR(c);
return 0;
}
/* Ending file layout: */
/* { } */
/* [3.14159]['b'][2] */
/* Note that the each Append alteration placed the */
/* object in the location immediately following the */
/* PreFirst position (resulting in the objects being */
/* ordered in the opposite order from the order in */
/* which they were written). */
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