[RC5] Re:

Tom Marshall tommym at owt.com
Tue Jan 27 21:12:31 EST 1998


Joe Zbiciak wrote:
> | > DOS has a limit of  128 characters for any command sequences.
> |
> | More specifically, it's command.com that has this limit. Using
> | another shell (like 4dos) allows one to create longer command lines
> | (like I do).
> 
> How?
> 
> <TECHNOBABBLE>
> 
> I thought the byte at offset 080h from the start of the PSP contained
> the length of the command line, and the "command tail" appeared between
> 081h and 0FFh--thus effectively limiting the commandline length to 127
> characters.  Or, is this limitation relaxed for .EXE files (which don't
> start at 0100h relative to the start of the PSP, like .COM files do)?
> 
> </TECHNOBABBLE>

I haven't "done DOS" in many, many moons but I seem to remember a
CMDLINE environment variable for 4DOS.  Environment variables have no
hard limitations that I know of (except that the shell only allocates a
fixed size block for the total environment).  Thus, your
extended-shell-aware app could check for a CMDLINE environment variable
and get an extended command line.

As far as I remember, the PSP still applies to EXE files.  I think it's
passed as DS:0000-DS:00FF.

Wow... brings back memories!

Tommy

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