From: Willem de Bruijn <willemb@xxxxxxxxxx>
Expand the epoll_wait page with epoll_pwait2, an epoll_wait variant
that takes a struct timespec to enable nanosecond resolution timeout.
int epoll_pwait2(int fd, struct epoll_event *events,
int maxevents,
const struct timespec *timeout,
const sigset_t *sigset);
Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx>
---
This is the same as an RFC sent earlier.
epoll_pwait2 is now merged in 5.11-rc1.
I'm not sure whether to send for manpages inclusion before 5.11
reaches stable ABI, or after. Erring on the side of caution. It
could still be reverted before then, of course.
---
man2/epoll_wait.2 | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)
diff --git a/man2/epoll_wait.2 b/man2/epoll_wait.2
index 36001e02bde3..21d63503a87f 100644
--- a/man2/epoll_wait.2
+++ b/man2/epoll_wait.2
@@ -22,7 +22,7 @@
.\"
.TH EPOLL_WAIT 2 2020-04-11 "Linux" "Linux Programmer's Manual"
.SH NAME
-epoll_wait, epoll_pwait \- wait for an I/O event on an epoll file descriptor
+epoll_wait, epoll_pwait, epoll_pwait2 \- wait for an I/O event on an epoll file descriptor
.SH SYNOPSIS
.nf
.B #include <sys/epoll.h>
@@ -32,6 +32,9 @@ epoll_wait, epoll_pwait \- wait for an I/O event on an epoll file descriptor
.BI "int epoll_pwait(int " epfd ", struct epoll_event *" events ,
.BI " int " maxevents ", int " timeout ,
.BI " const sigset_t *" sigmask );
+.BI "int epoll_pwait2(int " epfd ", struct epoll_event *" events ,
+.BI " int " maxevents ", const struct timespec *" timeout ,
+.BI " const sigset_t *" sigmask );
.fi
.SH DESCRIPTION
The
@@ -170,6 +173,25 @@ argument may be specified as NULL, in which case
.BR epoll_pwait ()
is equivalent to
.BR epoll_wait ().
+.SS epoll_pwait2 ()
+The
+.BR epoll_pwait2 ()
+system call is equivalent to
+.BR epoll_pwait ()
+except for the
+.I timeout
+argument. It takes an argument of type
+.I timespec
+to be able to specify nanosecond resolution timeout. This argument functions
+the same as in
+.BR pselect (2)
+and
+.BR ppoll (2).
+If
+.I timeout
+is NULL, then
+.BR epoll_pwait2 ()
+can block indefinitely.
.SH RETURN VALUE
On success,
.BR epoll_wait ()
@@ -217,6 +239,9 @@ Library support is provided in glibc starting with version 2.3.2.
.BR epoll_pwait ()
was added to Linux in kernel 2.6.19.
Library support is provided in glibc starting with version 2.6.
+.PP
+.BR epoll_pwait2 ()
+was added to Linux in kernel 5.11.
.SH CONFORMING TO
.BR epoll_wait ()
and
@@ -269,7 +294,9 @@ this means that timeouts greater than 35.79 minutes are treated as infinity.
.SS C library/kernel differences
The raw
.BR epoll_pwait ()
-system call has a sixth argument,
+and
+.BR epoll_pwait2 ()
+system calls have a sixth argument,
.IR "size_t sigsetsize" ,
which specifies the size in bytes of the
.IR sigmask
--
2.30.0.284.gd98b1dd5eaa7-goog
