Could you please give a reproducible example? On Fri, 14 Nov 2003 [EMAIL PROTECTED] wrote:
> Trying to copy the (binary) header of a input file directly > to an output file, I've had repeatable seg faults. The call: > > writeChar(hdr, outfh, nchars=6144) > > when hdr just contains one empty string seems to be the > culprit. The stack traces weren't all that illuminating, > with sig 11 in memory-related functions following this. But > in src/main/connections.c it looks like do_writechar doesn't > check the length of strings when given an explicit nchars > argument; so I think the strncpy() call will read too far. All R strings should be null-terminated, so strncpy will only copy the number of characters present (plus the null terminator) if less than n. I can see that writeChars might write rubbish out, but not why it should segfault. It is also unclear to me what to do in this case: flag a user error? > [This happened because I didn't remember that R lets null > terminate strings; so I did a readChar(infh, nchars=6144) > through some nulls at the start of the header, and ended up > with a much shorter string than I was expecting. As far as > I can tell do_readchar still behaves in these circumstances, > and in any case I can produce the fault without it.] > > Using readBin and writeBin with integer() and size=1 seems > to be the solution for header copying, but the faults still > seemed worth reporting. It's certainly the documented way. -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
