Path: utzoo!attcan!uunet!vsi!friedl
From: friedl@vsi.UUCP (Stephen J. Friedl)
Newsgroups: comp.lang.c
Subject: Re: putting stuff in the text segment
Summary: Problems with `cc -R' in BSD
Message-ID: <688@vsi.UUCP>
Date: 26 May 88 17:50:06 GMT
References: <3813@lynx.UUCP> <523@unh.UUCP>
Distribution: na
Organization: V-Systems, Inc. -- Santa Ana, CA
Lines: 37

In article <523@unh.UUCP>, jeff@unh.UUCP (Jeefrey E. F. Friedl) writes:
> In article <3813@lynx.UUCP>, m5@lynx.UUCP (Mike McNally) writes:
> > [How to put data in the text segment?]
> 
> [...]

> If you're using BSD at least, you can just compile the code where the
> initialized data is with the -R flag, which is passed to the assembler
> and indicates that all ".data" directives should be ".text".

Be careful with this: as I recall, *all* initialized statics go
into the .text and are readonly.  This means that:

        foo()
        {
        static int been_here = 0;

                if (! been_here)
                {
                        /* whatever */
                        been_here++;    /* <------ CORE DUMP HERE */
                }
        }

core dumps at the "been_here++"; a program can't modify its own
.text.  My solution was to declare:

        static int been_here;

and rely on the initialization to zero; an uninitialized static
always goes into the .bss.  This may have changed since 4.2.

-- 
Steve Friedl    V-Systems, Inc. (714) 545-6442    3B2-kind-of-guy
friedl@vsi.com    {backbones}!vsi.com!friedl   attmail!vsi!friedl

I'm jeff@unh's brother but I'm not proud of it.