Date: Thu, 24 Oct 2002 20:58:56 -0400 From: Craig Rodrigues <rodrigc@attbi.com> To: cvs-committers@FreeBSD.org Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/lib/libc/sys aio_cancel.2 aio_error.2 aio_read.2 aio_return.2 aio_suspend.2 aio_waitcomplete.2 aio_write.2 Message-ID: <20021024205856.A37333@attbi.com> In-Reply-To: <20021024211527.GC48760@starjuice.net>; from sheldonh@starjuice.net on Thu, Oct 24, 2002 at 11:15:27PM %2B0200 References: <200210221612.g9MGCR1p012070@repoman.freebsd.org> <20021022161820.GA57732@starjuice.net> <20021022164649.GS91539@elvis.mu.org> <20021024170737.A34595@attbi.com> <20021024211527.GC48760@starjuice.net>
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--zhXaljGHf11kAtnf Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Thu, Oct 24, 2002 at 11:15:27PM +0200, Sheldon Hearn wrote: > Please see the current incarnation of the page (rev 1.2) before doing > any more work on it. Patch incorporating changes from Garrett and Philippe. -- Craig Rodrigues http://www.gis.net/~craigr rodrigc@attbi.com --zhXaljGHf11kAtnf Content-Type: text/x-patch; charset=us-ascii Content-Disposition: attachment; filename="aio.4.diff" --- aio.4.orig Thu Oct 24 20:50:09 2002 +++ aio.4 Thu Oct 24 20:55:22 2002 @@ -46,6 +46,76 @@ It is available both as a kernel option for static inclusion and as a dynamic kernel module. .Pp +.Sh APPLICATION USAGE +Asynchronous I/O is specified as an option in +.St -p1003.1-2001 +and earlier standards. +A portable application must be prepared for the possibility that +asynchronous I/O may not be available, +and also that it may not be available at run-time for certain files or +types of file descriptors. +.Pp +The +.Dv _POSIX_ASYNCHRONOUS_IO +macro in +.Pa unistd.h +describes the compile-time support for +.Nm . +The following conditions are possible: +.Bl -inset -offset indent +.It Dv _POSIX_ASYNCHRONOUS_IO No is not defined . +The implementation provides no information about whether programs using +.Nm +can be compiled. +.It Dv _POSIX_ASYNCHRONOUS_IO No is defined to \-1 . +The implementation does not support the asynchronous I/O +feature; the +.Pa aio.h +header file and +.Fn aio_* +functions are not provided. +.It Dv _POSIX_ASYNCHRONOUS_IO No is defined to a positive integer . +The implementation supports the asynchronous I/O feature +unconditionally, for all files and all file descriptors. The +.Pa aio.h +header file and +.Fn aio_* +functions are provided. +.It Dv _POSIX_ASYNCHRONOUS_IO No is defined to zero . +The implementation optionally supports asynchronous I/O. +The +.Pa aio.h +header file and +.Fn aio_* +functions are provided. +However, the result of calling any +.Fn aio_* +function is undefined unless the application has checked that the +asynchronous I/O option is supported on the files or file descriptors +it plans to use, by calling the +.Xr pathconf 2 +or +.Xr fpathconf 2 +function with a +.Fa name +argument of +.Dv _PC_ASYNC_IO . +If +.Nm +is available for the specified file (or descriptor), +.Xr pathconf 2 +(or +.Xr fpathconf 2 ) +will return a positive integer which is equal to the value specified +for +.Dv _POSIX_VERSION +by the version of the standard the system implements. +.El +.Pp +These configuration parameters can be queried by shell scripts using +the +.Xr getconf 1 +program. .Sh SEE ALSO .Xr aio_cancel 2 , .Xr aio_error 2 , --zhXaljGHf11kAtnf-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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