Re: bug report

[Werner LEMBERG]

[David, maybe you can help here.  I've noted that recently a similar
problem has been discussed on the emacs-devel list, and maybe this
problem is related.

Here the original report; Mathew is using an SGI Octane with Irix 6.5:

  Error: geqn fails when it tries to write output to stdout.  This
  happens at line 378 of main.cc.  Doing a system call trace, it
  appears that stdout has been closed.  I added a line of code to
  print out the errno when the printf fails.  I get "stdout': Bad file
  number"

  It appears that stdout was closed long before the error.  In the
  trace I see "open" calls returning the value 1.

Does this sound familiar?]

> Something really strange.... my system trace shows that man closes
> file descriptors 0,1, and 2 just prior to execv-ing nroff.  Maybe
> the problem here is SGI's "man"??  I notice that when I run using
> the sgi nroff, eqn does not write to stdout.  Instead, nothing is
> written to stdout again until man does a "write" after calling
> ioctl(1, __OLD_TCGETA, <bad indirect __old_termio param - len 30>)
> OK
> 
> Maybe it isnt safe to call printf from with eqn without checking
> first that the IO file handles are still open??

AFAIK, stderr, stdin, and stdout are opened and closed automatically
at the start and end of the program.  If nothing explicitly closes the
handles, they should be always available.  There is some trickery to
duplicate streams in groff.cc IIRC, but none is really closed.
Anyway, this shouldn't affect eqn.


    Werner