X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/9bccf70c0258c7cac2dcb80011b2a964d884c552..bb59bff194111743b33cc36712410b5656329d3c:/bsd/man/man2/select.2 diff --git a/bsd/man/man2/select.2 b/bsd/man/man2/select.2 index cc00e641d..eeb8aceb8 100644 --- a/bsd/man/man2/select.2 +++ b/bsd/man/man2/select.2 @@ -37,25 +37,55 @@ .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 -.Fd #include -.Fd #include +.Fd #include +.\" +.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 -.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 -.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. @@ -64,7 +94,9 @@ The first 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 @@ -95,6 +127,11 @@ is non-zero if 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 , @@ -120,7 +157,7 @@ Any of .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 @@ -134,21 +171,74 @@ If .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 +.\" =========== +.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 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 +.Fa ndfs +is greater than FD_SETSIZE and _DARWIN_UNLIMITED_SELECT is not defined. .El +.Sh LEGACY SYNOPSIS +.Fd #include +.D1 "- or -" +.Fd #include +.Fd #include +.Fd #include +.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 , @@ -157,7 +247,8 @@ negative or too large. .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