From p.dalgaard@biostat.ku.dk  Sun Oct 31 12:30:01 1999
From: p.dalgaard@biostat.ku.dk (Peter Dalgaard BSA)
Date: 31 Oct 1999 13:30:01 +0100
Subject: read.table problem on Linux/Alpha (seg faults caused by isspace(R_EOF)) (PR#303)
In-Reply-To: ntakebay@bio.indiana.edu's message of "Sun, 31 Oct 1999 01:29:06 +0200 (MET DST)"
References: <199910302329.BAA17382@pubhealth.ku.dk>
Message-ID: <x24sf7lnli.fsf@blueberry.kubism.ku.dk>

ntakebay@bio.indiana.edu writes:

> Here is a fix.
> 
> --- R-0.65.1/src/main/scan.c.orig       Wed Sep 29 11:11:45 1999
> +++ R-0.65.1/src/main/scan.c    Fri Oct 29 17:34:22 1999
> @@ -124,7 +124,7 @@
>                 if (bufp >= &buffer[MAXELTSIZE - 2])
>                     continue;
>                 *bufp++ = c;
> -           } while (!isspace(c = scanchar()) && c != R_EOF);
> +           } while ((c = scanchar()) != R_EOF && !isspace(c));
....
> When the scanchar() returns R_EOF (=65535 #defined in src/include/Defn.h),
> isspace(R_EOF) seq-faults.  By switching the order of two conditions, I could
> get around with it.  I just made a test to see the behavior of isspace() by
> giving
> isspace(65535).  It seg-faults in both Linux/alpha and i386 (is it supposed
> to??).
> However, R on i386 doesn't seg-faults when the last line does not have newline.

Thanks. However, perhaps a better fix would be to change R_EOF? All
the isxxx macros/functions work by indexing an array designed to take
values between -128 and +255, so passing 65535 is playing with fire,
and we have many more instances littered all over the code, where I
don't feel absolutely sure that R_EOF couldn't sneak in.

Any one remember why R_EOF is different from the customary EOF of -1??

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907
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read.table problem on Linux/Alpha (seg faults caused by isspace(R_EOF)) (PR#303)
Peter Dalgaard BSA