Re: hurd/trans/hello.c changes

[Sergiu Ivanov]

Hello,

On Thu, Dec 24, 2009 at 12:32:53PM +0530, Shakthi Kannan wrote:
> --- On Thu, Dec 24, 2009 at 12:42 AM, Sergiu Ivanov
> | Printing to a file is nothing fancy: the fprintf functions should
> | suffice.
> \--
> 
> I would appreciate if I could see a working example. When I use
> fprintf(stdout, "message"); or fprintf(stderr, "error"); in a
> translator, and use it with:
> 
>   settrans -fgap /tmp/hello hello 1>out 2>err
> 
> neither of them are going into out or err, or the console. Probably, I
> am missing something here.

Translators do not normally have standard input or standard output.  I
think you could explicitly assign some files to stdin or stdout, but
initially these point to nothing (AIUI), so you have to explicitly
open a file before fprintf-ing to it.  As for stderr, I cannot tell
why it won't work, since I've never tried this and, unfourtunately, I
have too little time to check it now :-( (One could attach gdb to the
translator and inspect stderr, for instance.)

Also, I think using absolute paths for opening files for debug output
is better than relative paths, but I don't remember the exact
reasoning.  A candidate would be that passive translators do not
always get the working directory you would expect, but I'm not sure
whether this is applicable in you case.

Regards,
Sergiu