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storing in to a file and reading rom a file

Posted on 2002-06-14
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Last Modified: 2013-11-20
how to store value of a byte pointer to a file.and after storing how to read from a file and store that value into a byte pointer variable.for ex:
BYTE *p;p is having some value.thatvalue i have to store in to a file.and again i have to read that value from file and store into p .
it's very urgent.
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Question by:raju_r
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jhance earned 100 total points
ID: 7080347
It's not very useful storing a POINTER in a file as the pointer is not likely to be valid when the application is run again and the value is read and used.  But there is nothing stopping you from doing it....

Here's the C way:

FILE *fp;
BYTE *p;

// WRITE the value of p to a file

// Assume that p has some value set....
p = 0x12345678;


fp = fopen("pointerfile.dat", "wb");
if(fp == NULL){
  printf("Error opening file....\n");
  return;
}

// Note that we use the ADDRESS OF p (&p) and not p since
// we want to write the VALUE OF p and NOT the value of
// what p points to.
fwrite((LPVOID)&p, sizeof(BYTE *), 1, fp);

fclose(fp);

// READ the value of p from a file
fp = fopen("pointerfile.dat", "rb");
if(fp == NULL){
  // Whatever....
  return;
}

fread((LPVOID)&p, sizeof(BYTE *), 1, fp);
fclose(fp);
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Expert Comment

by:jhance
ID: 7080348
The MFC way of doing this is pretty much the same using CFile.
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