Open System Services Programmer's Guide

/**********************************************/
/* read the OSS file in a thread aware manner */
/**********************************************/
while (1)
{
nbytes = read(fd, iobuf, IOSIZE);
if (nbytes < 0)
{
if ((errno == EWOULDBLOCK) || (errno == EAGAIN))
{
/**************************************************************************/
/* NOTE that this code does not execute for regular (disk) files, because */
/* read() on a regular file never returns EWOULDBLOCK or EAGAIN */
/**************************************************************************/
ret = spt_fd_read_ready(fd, NULL);
if (ret != 0)
{
printf("*** ERROR in OSS_read_thread: spt_fd_read_ready()
failed w/err %d\n",ret);
exit(0);
}
}
else
{
printf("*** ERROR in OSS_read_thread: read() failed w/error
%d ***\n",errno);
exit(0);
}
}
else if (nbytes == 0) /* EOF */
{
break;
}
else /* read successful */
{
filesize += nbytes;
/*********************************************************************/
/* When doing Non-Blocking OSS I/O to diskfiles, it is a good */
/* idea to call sched_yield(), otherwise this thread won't give */
/* up control until the file is completely written. This is because */
/* write() never returns EWOULDBLOCK for a diskfile. */
/*********************************************************************/
sched_yield();
}
} /* while */
close(fd);
printf("==> OSS_read_thread() read %ld bytes from file %s\n", filesize,
OSS_read_file);
return(NULL);
}
352 Using the Standard POSIX Threads Library