bug in /dev/null

[Frank van Maarseveen]

On Solaris 2.5.1 the following program behaves differently depending
on redirecting standard input from /dev/null or from an empty file.
When redirected from an empty file select() immediately returns 1,
indicating that fd 0 can be read which is correct behaviour. However,
when redirecting input from /dev/null select times out after two seconds
as if it makes sense to wait for data to appear.

I suppose select() waits for the bug to come out ;-)

Any clues?

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/time.h>
#include <errno.h>
void main()
{
fd_set readfds;
int n;
struct timeval tv;

FD_ZERO(&readfds);
FD_SET(0, &readfds);
tv.tv_sec = 2;
tv.tv_usec = 0;
n = select(1, &readfds, NULL, NULL, &tv);
printf("n=%d, errno=%d\n", n, errno);
}

--
Frank van Maarseveen Senior Software Engineer
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[Casper H.S. Dik - Network Security Engineer]

[[ PLEASE DON'T SEND ME EMAIL COPIES OF POSTINGS ]]

f...@tasking.nl (Frank van Maarseveen) writes:

>On Solaris 2.5.1 the following program behaves differently depending
>on redirecting standard input from /dev/null or from an empty file.
>When redirected from an empty file select() immediately returns 1,
>indicating that fd 0 can be read which is correct behaviour. However,
>when redirecting input from /dev/null select times out after two seconds
>as if it makes sense to wait for data to appear.

>I suppose select() waits for the bug to come out ;-)

It's a bug (it is marked as fixed but somehow it never got fixed)

1171830 (I've now filed a new one: 4201274)

Casper
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