Re: [dpdk-users] librte_cmdline usage

[longtb5@viettel.com.vn]

Hi Oliver,

Yes that was exactly what I needed. Thanks.

--BL

> -----Original Message-----
> From: olivier.matz@6wind.com [mailto:olivier.matz@6wind.com]
> Sent: Monday, January 22, 2018 8:38 PM
> To: longtb5@viettel.com.vn
> Cc: users@dpdk.org
> Subject: Re: librte_cmdline usage
> 
> Hi,
> 
> On Mon, Jan 22, 2018 at 05:15:22PM +0700, longtb5@viettel.com.vn wrote:
> > Hi all,
> >
> > I'm writing an application where there already exists a cmdline. Users
> > can issue commands by typing from stdin. I want to support another
> > user interface where commands are read from sources other than stdin,
> > saved into a string buffer, then executed using the already existed
> cmd_parse_ctx_t.
> >
> > So far I have implemented this functionality using the
> > cmdline_interact() API like so (pseudo code).
> >
> > /* Initialization */
> > /* cmds_ctx is the existing command context
> >  * that I wish to reuse
> >  */
> > new_cl = cmdline_new(cmds_ctx, "", cmdbuf_fd, 1);
> >
> > /* Polling */
> > for ( ; ; ) {
> > 	snprintf(cmdbuf, cmdlen + 2, "%s\n", raw_string);
> > 	lseek(cmdbuf_fd, 0 , SEEK_SET);
> > 	cmdline_interact(new_cl);
> > }
> >
> > There are a couple of questions:
> >
> > 1. Using cmdline_interact() seems to be quite expensive. How can I
> > reduce this cost. Is there a leaner/more elegant way to implement this
> > using DPDK API or do I have to write my own code/change the lib?
> >
> > 2. How can I disable the behavior where every interaction is written
> > to stdout, i.e., to have no output what so ever. Again this is to
> > improve performance since writing to stdout is costly.
> 
> If my understanding is correct, you want to use the command line parser
> without the i/o (readline part). For this, you can directly call
cmdline_parse(cl,
> buffer). It will parse the given buffer and invokes the callback.
> 
> There will be no output on stdout done by the cmdline library. But it does
not
> prevent a command callback to call printf() or similar.
> 
> Olivier