Date: Wed, 17 Nov 1999 06:37:12 +0300 From: Seva "Semenov" <seva@mtelecom.ru> To: freebsd-hackers@FreeBSD.ORG Subject: fifo's select in 3.3 RELEASE Message-ID: <383222DF.164E86DB@mtelecom.ru>
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FreeBSD 3.3 and 3.2 RELEASE.
fifo has nothing to read,
why select(2) return > 0 without timeout?
in freeBSD 2.2.X select(2) return 0
(timeout) as expected.
# mkfifo fifo
# cat readfifo.c
#include <fcntl.h>
#include <err.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
int
main()
{
int fd;
fprintf(stderr,"opening fifo\n");
if((fd=open("fifo",O_RDONLY|O_NONBLOCK))<0)
err(errno,"can't open fifo");
fprintf(stderr,"fifo opend\n");
for(;;){
fd_set fds;
int r;
struct timeval tv;
size_t s;
char b[64];
tv.tv_sec=5;
tv.tv_usec=0;
FD_ZERO(&fds);
FD_SET(fd,&fds);
r=select(FD_SETSIZE,&fds,NULL,NULL,&tv);
if(r<0)
err(errno,"select return %d ",r);
if(r==0){
perror("timeout");
continue;
}
fprintf(stderr,"start reading\n");
s=read(fd,b,63);
if(s<0)
err(errno,"read fifo return %d",s);
if(!s){
perror("read null bites");
continue;
}
puts(b);
}
}
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