Xref: news2.mv.net comp.os.msdos.djgpp:627 From: jan AT stack DOT urc DOT tue DOT nl (Jan Oonk) Newsgroups: comp.os.msdos.djgpp Subject: Re: Issues with nearptr's. Date: 29 Jan 1996 10:59:28 +0100 Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands. Lines: 30 Message-ID: <4ei5q0$cdq@snail.stack.urc.tue.nl> References: <31096ecf DOT sandmann AT clio DOT rice DOT edu> NNTP-Posting-Host: snail.stack.urc.tue.nl To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Charles Sandmann (sandmann AT clio DOT rice DOT edu) wrote: : > I'd like to use nearptr's to access physical memory currently occupied : > by video hardware. SOunds pretty simple, no? Well, I've read rumours : > that there are dangers involved in setting the NEARPTR flag in my crt0 flags. : The only known dangers are that a stray pointer can destroy the interrupt : table, DOS, driver data, Windows, or anything else in memory. If you always : program without bugs, you have nothing to worry about :-) : > One problem I have noticed is that when running under gdb, gdb : > crashes when I use this flag and try to print out large data structures. : > Are there any other possible issues? What's really going on in there? : This really shouldn't be related, and I don't know why this would make : a difference. With nearptrs you could overwrite GDB's memory, but this : might actually be seen with the default non-move sbrk anyway, since the : debugger and program could end up with their memory laid out ABABAB. I tried the nearptr example! I got an compile-error: crt0_flag_nonmove_sbrk not declared or something it's not defined anywhere... i looked everywhere.. i am using djgpp v2 b4 gcc 2.7.1 -- This message was sent by Trax/SPiRiT! Please EMAIL all replys to Jan AT stack DOT urc DOT tue DOT nl