Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!uunet!husc6!mit-eddie!ll-xn!ames!amdahl!oliveb!felix!preston
From: preston@felix.UUCP (Preston Bannister)
Newsgroups: comp.sys.atari.st
Subject: Beckmeyer C-shell bug (was: Source for a system() routine needed)
Message-ID: <13782@felix.UUCP>
Date: Mon, 23-Nov-87 11:54:26 EST
Article-I.D.: felix.13782
Posted: Mon Nov 23 11:54:26 1987
Date-Received: Sat, 28-Nov-87 07:41:34 EST
References: <13021@felix.UUCP> <1845@chinet.UUCP>
Sender: daemon@felix.UUCP
Reply-To: preston@felix.UUCP (Preston Bannister)
Organization: FileNet Corp., Costa Mesa, CA
Lines: 62

In article <1845@chinet.UUCP> dag@chinet.UUCP (Daniel A. Glasser) writes:
>In article <13021@felix.UUCP> preston@felix.UUCP (Preston Bannister) writes:

>>Has anyone out there implemented a version of the system() library
>>routine that uses the Mark Williams/Beckmeyer scheme for passing long
>>argument lists?  

>>Unfortunately, the system() routine in the Mark Williams library does
>>not.  The argument list gets truncated after 127 characters.

>Not true!  The Mark Williams library DOES use the environment scheme
>for system()...  It calls up the shell, msh.prg, and msh calls up the
>command.  If you are getting truncated command lines, something is
>screwing around with the "ARGV" or "IOVECT" environment string and
>the runtime startup is not finding the parameters in the environment.

On further investigation, you're right...sort of.  The problem, as it
turns out, is that the Beckmeyer C-shell does not handle very long
single arguments.

The MWC system() passes through the string given to it as a single
argument.  I.e. the call:

	system("foo bar baz");

Becomes a call to the default shell with the following MWC extended
argument list appended to the environment (assume the SHELL environment
variable is set to 'shell.prg', the iovector is approximate):

	ARGV=CCCA??????????????????
	shell.prg
	-c
	foo bar baz

Note that the string passed to the system() call is passed through as
a single argument.  

I had the SHELL environment variable set to 'csh.prg', the Beckmeyer
C-shell.  When csh was given a single argument longer than 127
characters, it truncates the argument.

The shell supplied with MWC (msh) can handle single arguments that are
longer than 127 characters.  

So where does this leave us?  

1.  Use 'msh' for the default shell in makefiles where the argument
    list may be longer than 127 characters.  (I set the environment
    variable SHELL to 'msh.prg' at boot time with GEMBOOT).

2.  The system() function should be fixed to spilt up the command
    string passed to it into an argument list.  (My opinion).

3.  The Beckmeyer C-shell (and other shells :-) should be prepared to
    handle single arguments longer than 127 characters.  (My opinion).

--
Preston L. Bannister
USENET	   :	ucbvax!trwrb!felix!preston
BIX	   :	plb
CompuServe :	71350,3505
GEnie      :	p.bannister