read.table problem on Linux/Alpha (seg faults caused by isspace(R_EOF)) (PR#303)
Peter Dalgaard BSA
p.dalgaard@biostat.ku.dk
31 Oct 1999 13:30:01 +0100
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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