Xref: utzoo unix-pc.general:2207 comp.sys.att:5490 gnu.gcc:201
Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!rutgers!att!icus!lenny
From: lenny@icus.islp.ny.us (Lenny Tropiano)
Newsgroups: unix-pc.general,comp.sys.att,gnu.gcc
Subject: Re: gcc 1.33 compiled and working fine on UNIX pc/3B1
Message-ID: <598@icus.islp.ny.us>
Date: 9 Feb 89 17:49:00 GMT
References: <594@icus.islp.ny.us> <1092@banzai.UUCP>
Reply-To: lenny@icus.islp.ny.us (Lenny Tropiano)
Organization: ICUS Software Systems, Islip, New York
Lines: 45

In article <1092@banzai.UUCP> roger@banzai.UUCP (Roger Florkowski) writes:
|>In article <594@icus.islp.ny.us> lenny@icus.islp.ny.us (Me) write:
|>>The compiler compiled flawlessly with the stock UNIX pc compiler
....
|>A hint on using gcc:
|>
|>some programs 'like' it better if you use these flags:
|>
|>gcc -traditional -fwritable-strings
|>
...
|>-fwritable-strings	affects what gcc does with character strings.
|>			/lib/ccom allowed writable strings. (read man-page)
|>

It would be better to fix the kludgy code that is taking constants,
which the UNIX PC stock compiler puts in the "data" segment, and changing
the contents of them.

	char *mystring = "hello, world\n";

	Should go in the text segment (which the GNU gcc compiler does
	by default, unless specified with the -fwritable-strings option)
	which is sharable among processes on certain machines (I'm not
	sure how the UNIX pc handles it -- the old question of whether
	the "sticky-bit (t)" has any effect comes to mind again).

	It would not be good practice to modify "mystring" if it was
	initialized at compile time.  The UNIX PC stock /lib/ccom (C
	compiler) would allow this, because it places the string in
	the data segment, without -fwritable-strings, any attempt
	to modify the mystring variable under the GNU gcc compiler would
	cause a "Memory fault"

As the gcc documentation mentions, "constants should be constant!"
Of course if you feel that you don't want to bother hacking up bad
code to be correct, you can crutch on the -fwritable-strings compiler
flag.

-Lenny
-- 
Lenny Tropiano             ICUS Software Systems         [w] +1 (516) 582-5525
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