Comtrol eCos - Manual (Page 567)

Chapter 38. TCP/IP Library Reference
An ioctl() function call appeared in Version 7 AT&T UNIX.
BSD December 11, 1993 BSD
poll
POLL(2) System Calls Manual POLL(2)
NAME
poll - synchronous I/O multiplexing
SYNOPSIS
#include < poll.h>
int
poll(struct pollfd *fds, int nfds, int timeout);
DESCRIPTION
poll() provides a mechanism for reporting I/O conditions across a set of
file descriptors.
The arguments are as follows:
fds Points to an array of pollfd structures, which are defined as:
struct pollfd {
int fd;
short events;
short revents;
};
The fd member is an open file descriptor. The events and
revents members are bitmasks of conditions to monitor and condi-
tions found, respectively.
nfds The number of pollfd structures in the array.
timeout Maximum interval to wait for the poll to complete, in millisec-
onds. If this value is 0, then poll() will return immediately.
If this value is INFTIM (-1), poll() will block indefinitely
until a condition is found.
The calling process sets the events bitmask and poll() sets the revents
bitmask. Each call to poll() resets the revents bitmask for accuracy.
The condition flags in the bitmasks are defined as:
POLLIN Data is available on the file descriptor for reading.
POLLNORM Same as POLLIN.
POLLPRI Same as POLLIN.
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