xnu-1228.7.58.tar.gz

[apple/xnu.git] / bsd / man / man2 / select.2

diff --git a/bsd/man/man2/select.2 b/bsd/man/man2/select.2
index 39fd5d84b449fe7f7d063ed61b5e100d5e43a908..eeb8aceb8e467e3203afae274e6ee8b9476352ca 100644 (file)
--- a/bsd/man/man2/select.2
+++ b/bsd/man/man2/select.2
@@ -37,27 +37,55 @@
 .Dt SELECT 2
 .Os BSD 4.2
 .Sh NAME
 .Dt SELECT 2
 .Os BSD 4.2
 .Sh NAME

+.Nm FD_CLR ,
+.Nm FD_COPY ,
+.Nm FD_ISSET ,
+.Nm FD_SET ,
+.Nm FD_ZERO ,

 .Nm select
 .Nd synchronous I/O multiplexing
 .Sh SYNOPSIS
 .Fd #include <sys/select.h>
 .Nm select
 .Nd synchronous I/O multiplexing
 .Sh SYNOPSIS
 .Fd #include <sys/select.h>

-.D1 "- or -"
-.Fd #include <sys/types.h>
-.Fd #include <sys/time.h>
-.Fd #include <unistd.h>
+.\"
+.Ft void
+.Fo FD_CLR
+.Fa fd
+.Fa "fd_set *fdset"
+.Fc
+.Ft void
+.Fo FD_COPY
+.Fa "fd_set *fdset_orig"
+.Fa "fd_set *fdset_copy"
+.Fc

 .Ft int
 .Ft int

-.Fn select "int nfds" "fd_set *readfds" "fd_set *writefds" "fd_set *exceptfds" "struct timeval *timeout"
-.Fn FD_SET fd &fdset
-.Fn FD_CLR fd &fdset
-.Fn FD_ISSET fd &fdset
-.Fn FD_ZERO &fdset
+.Fo FD_ISSET
+.Fa fd
+.Fa "fd_set *fdset"
+.Fc
+.Ft void
+.Fo FD_SET
+.Fa fd
+.Fa "fd_set *fdset"
+.Fc
+.Ft void
+.Fo FD_ZERO
+.Fa "fd_set *fdset"
+.Fc
+.Ft int
+.Fo select
+.Fa "int nfds"
+.Fa "fd_set *restrict readfds"
+.Fa "fd_set *restrict writefds"
+.Fa "fd_set *restrict errorfds"
+.Fa "struct timeval *restrict timeout"
+.Fc

 .Sh DESCRIPTION
 .Fn Select
 examines the I/O descriptor sets whose addresses are passed in
 .Fa readfds ,
 .Fa writefds ,
 and
 .Sh DESCRIPTION
 .Fn Select
 examines the I/O descriptor sets whose addresses are passed in
 .Fa readfds ,
 .Fa writefds ,
 and

-.Fa exceptfds
+.Fa errorfds

 to see if some of their descriptors
 are ready for reading, are ready for writing, or have an exceptional
 condition pending, respectively.
 to see if some of their descriptors
 are ready for reading, are ready for writing, or have an exceptional
 condition pending, respectively.


@@ -66,7 +94,9 @@ The first
 descriptors are checked in each set;
 i.e., the descriptors from 0 through
 .Fa nfds Ns No -1
 descriptors are checked in each set;
 i.e., the descriptors from 0 through
 .Fa nfds Ns No -1

-in the descriptor sets are examined.
+in the descriptor sets are examined.  (Example: If you have set two file descriptors "4" and "17",
+.Fa nfds
+should  not be "2", but rather "17 + 1" or "18".)

 On return,
 .Fn select
 replaces the given descriptor sets
 On return,
 .Fn select
 replaces the given descriptor sets


@@ -97,6 +127,11 @@ is non-zero if
 is a member of
 .Fa fdset ,
 zero otherwise.
 is a member of
 .Fa fdset ,
 zero otherwise.

+.Fn FD_COPY &fdset_orig &fdset_copy
+replaces an already allocated 
+.Fa &fdset_copy
+file descriptor set with a copy of
+.Fa &fdset_orig .

 The behavior of these macros is undefined if
 a descriptor value is less than zero or greater than or equal to
 .Dv FD_SETSIZE ,
 The behavior of these macros is undefined if
 a descriptor value is less than zero or greater than or equal to
 .Dv FD_SETSIZE ,


@@ -122,7 +157,7 @@ Any of
 .Fa readfds ,
 .Fa writefds ,
 and
 .Fa readfds ,
 .Fa writefds ,
 and

-.Fa exceptfds
+.Fa errorfds

 may be given as nil pointers if no descriptors are of interest.
 .Sh RETURN VALUES
 .Fn Select
 may be given as nil pointers if no descriptors are of interest.
 .Sh RETURN VALUES
 .Fn Select


@@ -136,21 +171,74 @@ If
 .Fn select
 returns with an error,
 including one due to an interrupted call,
 .Fn select
 returns with an error,
 including one due to an interrupted call,

-the descriptor sets will be unmodified.
+the descriptor sets will be unmodified and the global variable
+.Va errno
+will be set to indicate the error.

 .Sh ERRORS
 An error return from
 .Fn select
 indicates:
 .Bl -tag -width Er
 .Sh ERRORS
 An error return from
 .Fn select
 indicates:
 .Bl -tag -width Er

+.\" ===========
+.It Bq Er EAGAIN
+The kernel was (perhaps temporarily) unable
+to allocate the requested number of file descriptors.
+.\" ===========

 .It Bq Er EBADF
 One of the descriptor sets specified an invalid descriptor.
 .It Bq Er EBADF
 One of the descriptor sets specified an invalid descriptor.

+.\" ===========

 .It Bq Er EINTR
 A signal was delivered before the time limit expired and
 before any of the selected events occurred.
 .It Bq Er EINTR
 A signal was delivered before the time limit expired and
 before any of the selected events occurred.

+.\" ===========

 .It Bq Er EINVAL
 The specified time limit is invalid.  One of its components is
 negative or too large.
 .It Bq Er EINVAL
 The specified time limit is invalid.  One of its components is
 negative or too large.

+.\" ===========
+.It Bq Er EINVAL
+.Fa ndfs
+is greater than FD_SETSIZE and _DARWIN_UNLIMITED_SELECT is not defined.

 .El
 .El

+.Sh LEGACY SYNOPSIS
+.Fd #include <sys/select.h>
+.D1 "- or -"
+.Fd #include <sys/types.h>
+.Fd #include <sys/time.h>
+.Fd #include <unistd.h>
+.Pp
+.Fo FD_SET
+.Fa fd
+.Fa &fdset
+.Fc ;
+.Pp
+.Fo FD_CLR
+.Fa fd
+.Fa &fdset
+.Fc ;
+.Pp
+.Fo FD_ISSET
+.Fa fd
+.Fa &fdset
+.Fc ;
+.Pp
+.Fo FD_COPY
+.Fa &fdset_orig
+.Fa &fdset_copy
+.Fc ;
+.Pp
+.Fo FD_ZERO
+.Fa &fdset
+.Fc ;
+.Sh COMPATIBILITY
+.Fn select
+now returns with
+.Va errno
+set to EINVAL when 
+.Fa nfds  
+is greater than FD_SETSIZE.
+Use a smaller value for
+.Fa nfds  
+or compile with -D_DARWIN_UNLIMITED_SELECT.

 .Sh SEE ALSO
 .Xr accept 2 ,
 .Xr connect 2 ,
 .Sh SEE ALSO
 .Xr accept 2 ,
 .Xr connect 2 ,


@@ -159,7 +247,8 @@ negative or too large.
 .Xr read 2 ,
 .Xr recv 2 ,
 .Xr send 2 ,
 .Xr read 2 ,
 .Xr recv 2 ,
 .Xr send 2 ,

-.Xr write 2
+.Xr write 2 ,
+.Xr compat 5

 .Sh BUGS
 Although the provision of
 .Xr getdtablesize 2
 .Sh BUGS
 Although the provision of
 .Xr getdtablesize 2