[pdftex] Another request for an enhancement to pdf(La)TeX

Hartmut Henkel hartmut_henkel at gmx.de
Wed Oct 27 01:01:40 CEST 2010

On Tue, 26 Oct 2010, James Quirk wrote:
> On Tue, 26 Oct 2010, André Wobst wrote:
> > At the moment it is not possible to stream the output of pdf(La)TeX
> > while it is generated. This is not a problem of having pdf(La)TeX
> > writing its output to a file with a certain name, as you could
> > easily set up a named pipe for that. I already tried this, but the
> > problem is seeking in the PDF being generated, namely when inserting
> > certain streams in the PDF output. The length of the stream is
> > inserted after the stream has been written by leaving some space
> > first and than seeking back to this position once the stream has
> > been written and its size is known. It is in the pdf_begin_stream
> > and pdf_end_stream functions in texk/web2c/pdftexdir/pdftex.web. (It
> > might be that there are other positions as well, but I'm not aware
> > of any other point where such seeks occur.)

It looks as if it has been so in pdftex maybe from the beginning, I
guess the idea was to spare objects (and the memory needed for storing
their info during the run). But such frugality should not be needed
anymore. A change, adding an extra /Length object after a stream, would
be almost trivial, also for object streams, which are just streams as
well, using the same length writing mechanism. There are also no other
seeks afaics. And it would give somewhat cleaner code.

But a larger problem seems to be to add to the existing .tex file kpse
search heuristics a pipe mechanism.

Regards, Hartmut

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