From: brunobg AT geocities DOT com (Bruno Barberi Gnecco)
Newsgroups: comp.os.msdos.djgpp
Subject: Trouble with many mallocs and reallocs
Date: 9 Aug 1998 09:36:00 -0500
Organization: Newscene Public Access Usenet News Service (http://www.newscene.com/)
Lines: 33
Message-ID: <35cdb08e.6406284@news3.newscene.com>
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

I'm writing a text editor, and using a pointer to dinamically allocated memory for
each line. Everytime a new byte is added or subtracted from the line, realloc is
called. Everything works fine until I type some lines. Then the program quits, and
returns a problem at malloc (it happens after I press enter, and it doesn't matter
how many characters I typed). The stderr is:

Exiting due to signal SIGSEGV
Page fault at eip=00008824, error=0004
eax=00000004 ebx=00000000 ecx=fffffffc edx=31de7500 esi=00000001 edi=00000001
ebp=00054dc0 esp=00054db8 program=d:/djgpp/creation/editor/editor.exe
cs: sel=01f7  base=8305a000  limit=ff7d3fff
ds: sel=01ff  base=8305a000  limit=ff7d3fff
es: sel=01ff  base=8305a000  limit=ff7d3fff
fs: sel=020f  base=00000000  limit=ffffffff
gs: sel=020f  base=00000000  limit=ffffffff
ss: sel=01ff  base=8305a000  limit=ff7d3fff

Call frame traceback EIPs:
  0x00008824
  0x00002822
  0x00004515
  0x00007db6

Debugging it, I find that the error is exactly at the line that allocates memory
to a new line (it allocates 1 byte). I'm running the Windows 95 DPMI server. What
may be the problem? Is there a better way to allocate memory? Can I use the DPMI
functions to allocae memory directly? How? Thanks! 
P.S.: this editor will be freeware and open-source. As soon as I can make it work
well enough to allow some editing, I'll release it. Maybe in one week...

"There's never enough time to do all the nothing you want" Bill Watterson 
Bruno Barberi Gnecco <brunobg AT geocities DOT com> ICQ #1383173 - PGP 5.0i user 
My other OS is Linux -=- http://graphx.home.ml.org -=- Electric Eng, Poli