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.1g”) 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 potentially 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. If newsigmask is a null pointer, pselect() behaves like select() with no setting or restoration of the signal mask.

See select(2) for a more detailed discussion of the semantics of this interface, and for macros used to manipulate the fd_set data type.

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

SEE ALSO

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

STANDARDS

The pselect() function conforms to IEEE Std 1003.1-2001 (“POSIX.1”).

HISTORY

The pselect() function first appeared in FreeBSD 5.0.

AUTHORS

The first implementation of pselect() function and this manual page were written by Garrett Wollman <wollman@FreeBSD.org>.