Re: Out of ptys
H. Peter Anvin (hpa@transmeta.com)
27 Aug 1998 05:34:52 GMT
Followup to: <Pine.LNX.3.95.980826132017.375A-100000@chaos.analogic.com>
By author: "Richard B. Johnson" <root@chaos.analogic.com>
In newsgroup: linux.dev.kernel
>
> Alan,
> This shows the problem I reported to the glibc folks about a year
> go. Note that both functions, good() and bad(), are identical except
> for the fds that I close.
>
> void bad()
> {
> int i;
> close(STDOUT_FILENO);
> i = fprintf(stdout, "Hello world!\n");
> if(i > 0)
> fprintf(stderr, "Bad! %d bytes copied to (closed) stdout...\n", i);
> else
> fprintf(stderr, "Good! (%d)\n", i);
> }
>
> void good()
> {
> int i;
> close(STDERR_FILENO);
> i = fprintf(stderr, "Hello world!\n");
> if(i > 0)
> fprintf(stdout, "Bad! %d bytes copied to (closed) stderr...\n", i);
> else
> fprintf(stdout, "Good! (%d)\n", i);
> }
>
This is perfectly understandable: stdout is a buffered stream, stderr
isn't. Your bug is mixing low-level functions (e.g. close()) with
stdio without an intervening fflush().
-hpa
--
PGP: 2047/2A960705 BA 03 D3 2C 14 A8 A8 BD 1E DF FE 69 EE 35 BD 74
See http://www.zytor.com/~hpa/ for web page and full PGP public key
I am Bahá'í -- ask me about it or see http://www.bahai.org/
"To love another person is to see the face of God." -- Les Misérables
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.altern.org/andrebalsa/doc/lkml-faq.html