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From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: truncate
Message-ID: <9023@jpl-devvax.JPL.NASA.GOV>
Date: 6 Aug 90 17:42:51 GMT
References: <46447@brunix.UUCP> <8977@jpl-devvax.JPL.NASA.GOV> <1990Aug4.154852.6468@robobar.co.uk>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 70

In article <1990Aug4.154852.6468@robobar.co.uk> ronald@robobar.co.uk (Ronald S H Khoo) writes:
: In article <8977@jpl-devvax.JPL.NASA.GOV> lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) writes:
: 
: >: Is it possible to truncate an open file in perl?  (like truncate(2)).
: >
: >It will be after the next patch, if your machine supports it.
: 
: I hope you won't forget those of us who pronounce "ftruncate" as
: "chsize" and have to utter -lx to load it when hacking Configure ...

Ok, it's in there, presuming chsize has the same arguments as ftruncate.
You'll have utter -lx to Configure yourself.

: BTW are you going to consider allowing limited setting of $< on systems
: that don't set[re]uid  as was suggested some time back ?  I can't remember
: who it was who suggested a nice way to hack that, but whoever you are, if you
: did implement it, can you mail me your patch ? I'll buy you a few beers
: at the next London Unix User Group meet you manage to attend :-)

You'll be able to say $< = $> and $> = $<.  The patch will look like this
(This is not an offical patch!!!  If you apply it, expect two rejected hunks
on the next official patch!!!):

*** /tmp/,RCSt1018459	Mon Aug  6 10:37:13 1990
--- stab.c	Mon Aug  6 10:31:46 1990
***************
***************
*** 366,372 ****
  	    if (setreuid((UIDTYPE)uid, (UIDTYPE)-1) < 0)
  		uid = (int)getuid();
  #else
! 	    fatal("setruid() not implemented");
  #endif
  #endif
  	    break;
--- 387,396 ----
  	    if (setreuid((UIDTYPE)uid, (UIDTYPE)-1) < 0)
  		uid = (int)getuid();
  #else
! 	    if (uid == euid)		/* special case $< = $> */
! 		setuid(uid);
! 	    else
! 		fatal("setruid() not implemented");
  #endif
  #endif
  	    break;
***************
*** 386,392 ****
  	    if (setreuid((UIDTYPE)-1, (UIDTYPE)euid) < 0)
  		euid = (int)geteuid();
  #else
! 	    fatal("seteuid() not implemented");
  #endif
  #endif
  	    break;
--- 410,419 ----
  	    if (setreuid((UIDTYPE)-1, (UIDTYPE)euid) < 0)
  		euid = (int)geteuid();
  #else
! 	    if (euid == uid)		/* special case $> = $< */
! 		setuid(euid);
! 	    else
! 		fatal("seteuid() not implemented");
  #endif
  #endif
  	    break;

Can I trade the beers for airfare?   :-)

Larry