From: jlrubin AT NO_MEAT_BYPRODUCTS DOT bway DOT net (Josh Rubin)
Newsgroups: comp.os.msdos.djgpp
Subject: Why is malloc allocating every other page?
Date: Tue, 07 Oct 1997 06:56:05 GMT
Message-ID: <3439dc3c.165049@news2.bway.net>
NNTP-Posting-Host: 205.198.117.34
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To: djgpp AT delorie DOT com
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The test program below allocates blocks of 4000 bytes,
which should fit easily in a page even with the malloc
overhead.
--> malloc allocates *every other* page! <--
(the same thing happens with smaller blocks, like 3000 bytes)

--------------
#include <stdio.h>
#include <stdlib.h>

int main()
{
  int n;
  void *p;
  for (n=0;n<10;++n) {
    p = malloc(4000);    /* should fit in 1 page, even with overhead
*/
    printf(" %x\n",(int)p);
  }
  return 0;
}
--------------

 52000
 59000
 5b000
 5d000
 5f000
 61000
 63000
 65000
 67000
 69000

Strip the all-caps text from my address before replying by email.
 Josh Rubin