Re: [PATCH v5 28/35] io_cancel.2: Use syscall(SYS_...); for system calls without a wrapper

["Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>]

Hi  Alex.

On 4/4/21 1:58 PM, Alejandro Colomar wrote:
> In this case there's a wrapper provided by libaio,
> but this page documents the raw kernel syscall.

Okay.

Patch applied.

Thanks,

Michael


> 
> Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
> ---
>  man2/io_cancel.2 | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/man2/io_cancel.2 b/man2/io_cancel.2
> index e09984ecd..248fe5791 100644
> --- a/man2/io_cancel.2
> +++ b/man2/io_cancel.2
> @@ -9,14 +9,13 @@
>  io_cancel \- cancel an outstanding asynchronous I/O operation
>  .SH SYNOPSIS
>  .nf
> -.BR "#include <linux/aio_abi.h>" "          /* Defines needed types */"
> +.BR "#include <linux/aio_abi.h>" "    /* Definition of needed types */"
> +.BR "#include <sys/syscall.h>" "      /* Definition of " SYS_* " constants */"
> +.B #include <unistd.h>
>  .PP
> -.BI "int io_cancel(aio_context_t " ctx_id ", struct iocb *" iocb ,
> -.BI "              struct io_event *" result );
> +.BI "int syscall(SYS_io_cancel, aio_context_t " ctx_id ", struct iocb *" iocb ,
> +.BI "            struct io_event *" result );
>  .fi
> -.PP
> -.IR Note :
> -There is no glibc wrapper for this system call; see NOTES.
>  .SH DESCRIPTION
>  .IR Note :
>  this page describes the raw Linux system call interface.
> @@ -68,10 +67,7 @@ The asynchronous I/O system calls first appeared in Linux 2.5.
>  is Linux-specific and should not be used
>  in programs that are intended to be portable.
>  .SH NOTES
> -Glibc does not provide a wrapper for this system call.
> -You could invoke it using
> -.BR syscall (2).
> -But instead, you probably want to use the
> +You probably want to use the
>  .BR io_cancel ()
>  wrapper function provided by
>  .\" http://git.fedorahosted.org/git/?p=libaio.git
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/