linux_module_learn/examples/misc-progs/polltest.c

48 lines
1.2 KiB
C

/*
* Test out reading with poll()
* This should run with any Unix
*
* Copyright (C) 2003 Alessandro Rubini and Jonathan Corbet
* Copyright (C) 2003 O'Reilly & Associates
*
* The source code in this file can be freely used, adapted,
* and redistributed in source or binary form, so long as an
* acknowledgment appears in derived source files. The citation
* should list that the code comes from the book "Linux Device
* Drivers" by Alessandro Rubini and Jonathan Corbet, published
* by O'Reilly & Associates. No warranty is attached;
* we cannot take responsibility for errors or fitness for use.
*
* $Id: polltest.c,v 1.1 2003/02/07 18:01:38 corbet Exp $
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/poll.h>
#include <fcntl.h>
char buffer[4096];
int main(int argc, char **argv)
{
struct pollfd pfd;
int n;
fcntl(0, F_SETFL, fcntl(0,F_GETFL) | O_NONBLOCK); /* stdin */
pfd.fd = 0; /* stdin */
pfd.events = POLLIN;
while (1) {
n=read(0, buffer, 4096);
if (n >= 0)
write(1, buffer, n);
n = poll(&pfd, 1, -1);
if (n < 0)
break;
}
perror( n<0 ? "stdin" : "stdout");
exit(1);
}