pselect(3)

NAME

pselect - synchronous I/O multiplexing a la POSIX.1g

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <sys/select.h>
int
pselect(int  nfds,  fd_set  *  restrict  readfds,  fd_set  *
restrict writefds,
        fd_set * restrict exceptfds,
        const struct timespec * restrict timeout,
        const sigset_t * restrict newsigmask);

DESCRIPTION

The pselect() function was introduced by IEEE Std

1003.1g-2000
(``POSIX.1'') as a slightly stronger version of select(2).

The nfds,
readfds, writefds, and exceptfds arguments are all identical

to the analogous arguments of select(). The timeout argument in

pselect() points to
a const struct timespec rather than the (modifiable) struct

timeval used
by select(); as in select(), a null pointer may be passed to

indicate
that pselect() should wait indefinitely. Finally,

newsigmask specifies a
signal mask which is set while waiting for input. When

pselect()
returns, the original signal mask is restored.

See select(2) for a more detailed discussion of the seman

tics of this
interface, and for macros used to manipulate the fd_set data

type.

IMPLEMENTATION NOTES

The pselect() function is implemented in the C library as a

wrapper
around select().

RETURN VALUES

The pselect() function returns the same values and under the

same conditions as select().

ERRORS

The pselect() function may fail for any of the reasons docu

mented for
select(2) and (if a signal mask is provided) sigprocmask(2).

SEE ALSO

kqueue(2), poll(2), select(2), sigprocmask(2)

STANDARDS

The pselect() function conforms to .

HISTORY

The pselect() function first appeared in FreeBSD 5.0.

AUTHORS

The pselect() function and this manual page were written by

Garrett
Wollman <wollman@FreeBSD.org>.

BSD June 16, 2002

BSD