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From: mikpe@IDA.LiU.SE (Mikael Pettersson)
Newsgroups: comp.lang.lisp.x
Subject: probable bug in xscheme
Summary: xsetfposition() interacts with xlgetc() and xlungetc()
Message-ID: <1991Jan28.091929.15518@ida.liu.se>
Date: 28 Jan 91 09:19:29 GMT
Sender: news@ida.liu.se (News Subsystem)
Organization: CIS Dept, Univ of Linkoping, Sweden
Lines: 19

There appears to be a bug in xsetfposition() (xlfun2.c).
Suppose the input file contains the characters #\5, #\Space
and #\; . Suppose we've done a (read) from the file, reading
5. Then #\Space will have been read and then pushed back
again by xlungetc(). Now let's rewind the port by doing
a (set-file-position! <the-port> 0 0). Then the next character
read from the port will still be that #\Space instead of the
#\5. Definitely un-cool :-(

The fix is to insert a line:

	setsavech(fptr, '\0');

just before the line in xsetfposition() that calls fseek().

/Mike
--
Mikael Pettersson, Dept of Comp & Info Sci, University of Linkoping, Sweden
email: mpe@ida.liu.se or ...!{mcsun,munnari,uunet,unido,...}!sunic!liuida!mpe