On Thu, Jan 31, 2008 at 02:28:58PM +0100, Jens Axboe wrote: >On Thu, Jan 31 2008, Michael Kerrisk wrote: >> >> >> Jens Axboe wrote: >> > On Thu, Jan 31 2008, Michael Kerrisk wrote: >> >> Hi Cong, >> >> >> >> WANG Cong wrote: >> >>> Hi, Michael and list! >> >>> >> >>> I found two problems in the man pages. The first one should >> >>> be a bug. It is that the type of the 2nd and 4th arguments >> >>> of splice(2) is wrong. The current prototype of splice(2) >> >>> in current man page is: >> >>> >> >>> long splice(int fd_in, off_t *off_in, int fd_out, >> >>> off_t *off_out, size_t len, unsigned int flags); >> >>> >> >>> However, they should be 'loff_t' instead of 'off_t'. If we >> >>> use 'off_t', gcc will generate a warning. Patch is in the end >> >>> of this email and it's against 2.76 release. ;) >> >> Thanks for spotting that. Fixed as you suggest, for man-pages-2.77. >> >> >> >>> The second one is a bit confused. The example given in tee(2) >> >>> even can not run normally. I got this error: >> >>> >> >>> $ ./example bar.txt >> >>> tee: Invalid argument >> >>> >> >>> I looked at tee(2), it is said that: >> >>> >> >>> EINVAL fd_in or fd_out does not refer to a pipe; or fd_in and fd_out >> >>> refer to the same pipe. >> >>> >> >>> So the first two arguments of tee(2) in the example is wrong, >> >>> since neither STDIN_FILENO nor STDOUT_FILENO refers to a pipe. >> >>> But I am not so sure, because I am new to tee(2). ;) If you can >> >>> comfirm this is really a bug, I can send a patch to fix this too. >> >>> >> >>> I have checked the newest release of man pages and my kernel version >> >>> is 2.6.21-1.3194.fc7. Did I miss something obvious? >> >> I'm not sure. Perhaps Jens, the implementer of tee(2) can provide a little >> >> help. Jens, what's an example of a command line for running the example >> >> program in the tee.2 man page? >> > >> > It's not a bug, it should be run as: >> > >> > $ echo hello | ./example output_file | cat >> > >> > so that both stdin and stdout are pipes, as described in the man page. >> > The man page is correct. I think man page should mention about this usage. >> >> Hi jens, >> >> Yes, I guessed you probably should run it like that. And it does produce >> the expected output on stdout. However, the command then blocks, and if >> one types control-C, the output_file is empty. How should this program be >> terminated so that something does end up in the output_file? > >See ktee.c from the splice sample repo, it works correctly: > >axboe@carl:~/git/splice> echo hello | ./ktee outfile | cat >hello >axboe@carl:~/git/splice> cat outfile >hello > >I don't have the tee(2) man page here so can't verify, but try and >compare them! > I have the same problem here with what Michael mentioned. But my output file is *not* empty. Shown below: $ echo hello | ./tee fooo.txt | cat hello <=== here blocked, type ctrl+c, exit $ cat fooo.txt hello My kernel version is 2.6.21-1.3194.fc7. Thank you! - To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
