/* Gamelon(tm) File I/O Library Sample Code C Language */
/* (C)1994 Menai Corporation(tm) Released for public use */
/* Example 9a. How to read the contents of stored objects */
/* when structure of the file is known. */
/* When the program knows the structure of the file, the */
/* program may simply move from object to object within */
/* the file, reading the contents of each object using */
/* datatypespecific read calls. For example, if the */
/* contents of a particular file (or of an aggregate */
/* within a file) are an integer value 14, a character */
/* value 'F' and a string value "Wherefore art thou, */
/* Romeo?", the function calls to read such a file could */
/* be as follows: */
/* Beginning file layout: */
/* { } */
/* [14]['F']["Wherefore art thou, Romeo?"] */
#include <stdlib.h>
#include <stdio.h>
#include "gfcursor.h"
int main(void) {
int valid;
short i;
char ch;
char *strptr;
size_t strsize;
CURSOR *c = new_CURSOR(NULL,
"newfile",
AM_SHARED,
NULL,
0);
eCursorQueryValid(c, &valid);
if (!valid)
exit(1);
eCursorMoveIn(c);
eObjReadShort(c, &i);
eCursorMoveNext(c, OT_OBJ);
eObjReadChar(c, &ch);
eCursorMoveNext(c, OT_OBJ);
eObjQueryDataSize(c, &strsize);
strptr = malloc(strsize);
eObjReadString(c, strptr, strsize);
printf("i = %hd\n", i);
printf("ch = %c\n", ch);
printf("strptr = %s\n", strptr);
free(strptr);
delete_CURSOR(c);
return 0;
}
/* Program output: */
/* i = 14 */
/* ch = F */
/* strptr = Wherefore art thou, Romeo? */
/* The ObjRead functions are overloaded; as a result, */
/* all the ObjRead calls look similar. The parameters */
/* of each function call distinguish the exact */
/* function called to read information from the */
/* object. Note that in order to properly read the */
/* object containing the string value, the programmer */
/* must first query the object for its datasize, in */
/* order to allocate enough memory for the string, or */
/* the programmer can just use a large preallocated */
/* block of memory. The size of the block of memory */
/* is then passed to the ObjRead function. */
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