[comp.lang.c] Saving bitmaps to file in Microsoft C

eweb@ccvax.ucd.ie (02/28/90)

My problem is that I'm trying to write bitmaps, to a file for 
future use. The program compiles okay but doesn't read the images 
back in. If I introduce a bug into the program, (e.g. an undeclared
variable) I get warnings about converting near pointers to far pointers.

  int x1, y1, x2, y2;
  unsigned int size;
  void *ptr;
  
  size = (unsigned int) _imagesize(x1,y1,x2,y2);
  ptr = malloc(size);
  _getimage(x1,y1,x2,y2,ptr);
  fwrite(&size, sizeof(unsigned int), 1, fp);
  fwrite(ptr, size, 1, fp);


and then later

  fread(&size, sizeof(unsigned int), 1, fp);
  ptr = malloc(size);
  fread(ptr, size, 1, fp);
  _putimage(x1,y1,ptr,_GXOR);

I'd prefer to know what I'm doing wrong, but if you can provide code, but 
can't provide an answer, well I'm not that proud....


Eamonn Webster                       eweb@ccvax.ucd.ie
Department of Computer Science       eweb@ccvax.bitnet
University College Dublin
Belfield
Dublin 4
Ireland

I never had an original thought in my life, so views expressed must be
someone else's....