diff options
Diffstat (limited to 'lib/libc/sys/aio_write.2')
| -rw-r--r-- | lib/libc/sys/aio_write.2 | 63 |
1 files changed, 52 insertions, 11 deletions
diff --git a/lib/libc/sys/aio_write.2 b/lib/libc/sys/aio_write.2 index a3268e50ea90..601515b0e7b0 100644 --- a/lib/libc/sys/aio_write.2 +++ b/lib/libc/sys/aio_write.2 @@ -24,11 +24,12 @@ .\" .\" $FreeBSD$ .\" -.Dd August 19, 2016 +.Dd January 2, 2021 .Dt AIO_WRITE 2 .Os .Sh NAME -.Nm aio_write +.Nm aio_write , +.Nm aio_writev .Nd asynchronous write to a file (REALTIME) .Sh LIBRARY .Lb libc @@ -36,28 +37,48 @@ .In aio.h .Ft int .Fn aio_write "struct aiocb *iocb" +.In sys/uio.h +.Ft int +.Fn aio_writev "struct aiocb *iocb" .Sh DESCRIPTION The .Fn aio_write -system call allows the calling process to write -.Fa iocb->aio_nbytes -from the buffer pointed to by -.Fa iocb->aio_buf +and +.Fn aio_writev +system calls allow the calling process to write to the descriptor .Fa iocb->aio_fildes . -The call returns immediately after the write request has been enqueued +.Fn aio_write +will write +.Fa iocb->aio_nbytes +from the buffer pointed to by +.Fa iocb->aio_buf , +whereas +.Fn aio_writev +gathers the data from the +.Fa iocb->aio_iovcnt +buffers specified by the members of the +.Fa iocb->aio_iov +array. +Both syscalls return immediately after the write request has been enqueued to the descriptor; the write may or may not have completed at the time the call returns. If the request could not be enqueued, generally due to invalid arguments, the call returns without having enqueued the request. .Pp +For +.Fn aio_writev +the +.Fa iovec +structure is defined in +.Xr writev 2 . +.Pp If .Dv O_APPEND is set for .Fa iocb->aio_fildes , -.Fn aio_write -operations append to the file in the same order as the calls were +write operations append to the file in the same order as the calls were made. If .Dv O_APPEND @@ -103,6 +124,8 @@ The asynchronous I/O control buffer .Fa iocb should be zeroed before the .Fn aio_write +or +.Fn aio_writev system call to avoid passing bogus context information to the kernel. .Pp Modifications of the Asynchronous I/O Control Block structure or the @@ -114,14 +137,20 @@ is past the offset maximum for .Fa iocb->aio_fildes , no I/O will occur. .Sh RETURN VALUES -.Rv -std aio_write +.Rv -std aio_write aio_writev .Sh ERRORS The .Fn aio_write -system call will fail if: +and +.Fn aio_writev +system calls will fail if: .Bl -tag -width Er .It Bq Er EAGAIN The request was not queued because of system resource limitations. +.It Bq Er EFAULT +Part of +.Fa aio_iov +points outside the process's allocated address space. .It Bq Er EINVAL The asynchronous notification method in .Fa iocb->aio_sigevent.sigev_notify @@ -134,10 +163,14 @@ are unsafe and unsafe asynchronous I/O operations are disabled. .Pp The following conditions may be synchronously detected when the .Fn aio_write +or +.Fn aio_writev system call is made, or asynchronously, at any time thereafter. If they are detected at call time, .Fn aio_write +or +.Fn aio_writev returns -1 and sets .Va errno appropriately; otherwise the @@ -203,11 +236,19 @@ system call is expected to conform to the .St -p1003.1 standard. +.Pp +The +.Fn aio_writev +system call is a FreeBSD extension, and should not be used in portable code. .Sh HISTORY The .Fn aio_write system call first appeared in .Fx 3.0 . +The +.Fn aio_writev +system call first appeared in +.Fx 13.0 . .Sh AUTHORS This manual page was written by .An Wes Peters Aq Mt wes@softweyr.com . |