Path: utzoo!attcan!uunet!aplcen!uakari.primate.wisc.edu!sdd.hp.com!usc!apple!archer!dwb
From: dwb@archer.apple.com (David W. Berry)
Newsgroups: comp.unix.aux
Subject: Re: Problem in sscanf with gcc-1.37 ?
Keywords: sscanf gcc
Message-ID: <9458@goofy.Apple.COM>
Date: 27 Jul 90 16:24:05 GMT
References: <2204@s3.ireq.hydro.qc.ca>
Sender: usenet@Apple.COM
Organization: Apple Computer
Lines: 22

In article <2204@s3.ireq.hydro.qc.ca> lamarche@ireq.hydro.qc.ca () writes:
	What you're seeing is a side effect of the fact that gcc
puts strings into text space.  To defeat this you can specify the
-fwritable-strings flag to gcc.

>main  ()
>{
>   char works[] = "Works 1 2";
	This allocates 10 bytes on the stack and then copies a string
from text space to the stack space.  Under most C compilers, it isn't
even allowed...

>   char* fails = "Fails 1 2";
	This allocates 4 bytes on the stack and puts a pointer to the
string in text space in the stack space.

Since the data that fails points to is not writable, when _doscan trys
to do an ungetc, it fails with a buserror.

	David
	David W. Berry			A/UX Toolbox Engineer
	dwb@apple.com