Path: utzoo!utgpu!watmath!iuvax!cica!tut.cis.ohio-state.edu!pt.cs.cmu.edu!thewalt
From: thewalt@RITZ.ce.cmu.edu (Chris Thewalt)
Newsgroups: gnu.gcc.bug
Subject: gcc 1.36 and -fwritable-strings
Message-ID: <THEWALT.89Oct19125053@RITZ.ce.cmu.edu>
Date: 19 Oct 89 16:50:53 GMT
Distribution: gnu
Organization: Dept. of Civil Engineering, Carnegie Mellon University,
	Pittsburgh, PA
Lines: 59

Hello. I am using gcc 1.36 on a MicroVAX running Ultrix 2.2.  I tried
to compile the following simple program without the -fwritable strings
and get a bus error, but it works with the flag. I don't quite
understand this since I am not attempting to write into any string
constants. A script of the session follows:

Script started on Thu Oct 19 12:41:58 1989

% cat ttt.c
#include <stdio.h>

main()
{
char *p[3], w[27], *q = w;
register int i;

sscanf("plan-plan","%s",p[0] = q);
q += strlen(q) + 1;
sscanf("lin-lin",  "%s",p[1] = q); 
q += strlen(q) + 1;
sscanf("lin-plan", "%s",p[2] = q); 

for(i=0;i < 3;++i)
   printf("%s\n",p[i]);

}

% gcc -v -o ttt ttt.c
gcc version 1.36
 /usr/misc/.gnu/lib/compilers/gcc-cpp -v -undef -D__GNUC__ -Dvax -Dunix -D__vax__ -D__unix__ ttt.c /usr/tmp/cc022254.cpp
GNU CPP version 1.36
 /usr/misc/.gnu/lib/compilers/gcc-cc1 /usr/tmp/cc022254.cpp -quiet -dumpbase ttt.c -version -o /usr/tmp/cc022254.s
GNU C version 1.36 (vax) compiled by GNU C version 1.36.
default target switches: -munix
 as -o ttt.o /usr/tmp/cc022254.s
 ld -o ttt /lib/crt0.o ttt.o /usr/misc/.gnu/lib/compilers/gcc-gnulib -lc

% ttt
Bus error

% gcc -fwritable-strings -v -o ttt ttt.c
gcc version 1.36
 /usr/misc/.gnu/lib/compilers/gcc-cpp -v -undef -D__GNUC__ -Dvax -Dunix -D__vax__ -D__unix__ ttt.c /usr/tmp/cc022260.cpp
GNU CPP version 1.36
 /usr/misc/.gnu/lib/compilers/gcc-cc1 /usr/tmp/cc022260.cpp -quiet -dumpbase ttt.c -fwritable-strings -version -o /usr/tmp/cc022260.s
GNU C version 1.36 (vax) compiled by GNU C version 1.36.
default target switches: -munix
 as -o ttt.o /usr/tmp/cc022260.s
 ld -o ttt /lib/crt0.o ttt.o /usr/misc/.gnu/lib/compilers/gcc-gnulib -lc

% ttt
plan-plan
lin-lin
lin-plan
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Christopher Robin Thewalt		These opinions are not necessarily
thewalt@ce.cmu.edu			shared by my employer...
Carnegie Mellon University