Subject: semantics of off_t changes
To: None <>
From: Matthieu Herrb <>
List: current-users
Date: 04/11/1994 19:09:24
While I was browsing through X sources to propagate the off_t change,
the following observation came to my mind:

 The fact that off_t is 64 bits while size_t is still 32 bits means
 that a file cannot allways be loaded in memory in one read().

This is quite awful ! X sources (and other) are full of code like:

	fstat(fd, &st);
	buf = malloc(st.st_size);
	if (buf == NULL) {
	   /* error */
	if (read(fd, buf, st.st_size) != st.st_size) {
	   /* error */

which obviously can fail if the file is large enough. 
In the case of X, I suppose that (st.st_size > 2^31) is an error
condition anyway by in the general case, such code has to be replaced
by an mmap() call (which does take an off_t size).

Comments ?