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RE: strlen on NULL, final test
- To: GNU-WIN32%CYGNUS dot COM at bamp01 dot sternwarte dot uni-erlangen dot de
- Subject: RE: strlen on NULL, final test
- From: "Michael Lemke, Sternwarte Bamberg, Phone: +49-951-9522216" <ai26 at sternwarte dot uni-erlangen dot de>
- Date: Thu, 14 May 1998 13:12:38 MET-1MET DST
- CC: ai26 at sternwarte dot uni-erlangen dot de
In a message of Wed, 13 May 1998 10:37:34 -0400 (EDT)
Received on Thu, 14 May 1998 11:52:22 MET-1MET DST
Ron G. Minnich <rminnich@sarnoff.com> wrote to gnu-win32@cygnus.com
>to finish this off once and for all, someone raised the question of a
>strlen that might test the argument to see if it's equal to 0, and then
>return 0.
>
>First, the empty string and the null string are different, and length of
>a null string has no meaning.
>Second, if you have null pointers, as others say, fix your code.
>
>But, even though it's a bad idea, who knows: someone might do it.
>
>bash$ cat test.c
>main()
>{
> (void) strlen((char *) 0);
>}
>
>bash$ cc test.c
>bash$ ./a.out
>Segmentation fault (core dumped)
>bash$
>
>Again: linux, freebsd, sunos, solaris.
>
Another data point:
LUCKY> cc x
(void) strlen((char *) 0);
.........^
%CC-I-IMPLICITFUNC, In this statement, the identifier "strlen" is implicitly dec
lared as a function.
at line number 3 in file TMP:[AI26]X.C;1
LUCKY> link x
LUCKY> run x
%SYSTEM-F-ACCVIO, access violation, reason mask=00, virtual address=000000000000
0000, PC=FFFFFFFF8050E8E8, PS=0000001B
%TRACE-F-TRACEBACK, symbolic stack dump follows
image module routine line rel PC abs PC
0 0000000000000000 FFFFFFFF8050E8E8
X X main 3 00000000000000C8 00000000000200C8
X X __main 0 0000000000000070 0000000000020070
0 FFFFFFFF827530F8 FFFFFFFF827530F8
LUCKY> sh sys/noproc/fu
OpenVMS V7.1-1H1 on node LUCKY 14-MAY-1998 13:03:52.43 Uptime 1 01:31:06
Digital AlphaPC 164 500 MHz
LUCKY> cc/vers
DEC C V5.7-004 on OpenVMS Alpha V7.1-1H1
--
Michael Lemke
Sternwarte Bamberg, University of Erlangen-Nürnberg, Germany
(lemke@sternwarte.uni-erlangen.de or michael@astro.as.utexas.edu)
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