[tex-k] portability of format dumps

[Norbert Preining]

Dear all

I would like to know what is ther current status of format dump file's
portability between architectures.
(status: texlive 2015 sources)

I remember faintly that at some point it was possible to use
format dumps within the same endian-class, but it was not possible
to switch to a different-endian system.

Is this still the case, are there any other restrictions concerning
format dump reuse across platforms?

Background: Debian uses multi-arch systems and would like to have as many
packages marked up as arch-independent so that one can use whatever arch
that is installed

Thanks

Norbert

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PREINING, Norbert http://www.preining.info
JAIST, Japan TeX Live & Debian Developer
GPG: 0x860CDC13 fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13
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[Akira Kakuto]

Hi Norbert,

Post by Norbert Preining
I remember faintly that at some point it was possible to use
format dumps within the same endian-class, but it was not possible
to switch to a different-endian system.

The do_dump() in texmfmp.c seems to show that
format files are independent of platforms if
NO_DUMP_SHARE is not defined.

[Norbert Preining]

Dear Akira,

Post by Akira Kakuto
format files are independent of platforms if
NO_DUMP_SHARE is not defined.

It seems that this is also actually the case. I have made
now experiments with copying dump files from my machine to
some different endian machine, and there was no hickup.

Thanks!!

Norbert

------------------------------------------------------------------------
PREINING, Norbert http://www.preining.info
JAIST, Japan TeX Live & Debian Developer
GPG: 0x860CDC13 fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13
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[Karl Berry]

Hi Norbert,

In theory, as Akira said, .fmt/etc files from web2c are and have been
100% portable across platforms, independent of endian-ness, Windows
vs. Unix-ness, and everything else. (I seem to recall that being one of
the first changes I made to web2c back in the mid/late-80s.)

There was a bug a few years ago, possibly present for more than one
year, where the format files were endian-dependent. That was never
intentionally the case.

(I wish we would reliably test this every year against the bug coming
back, but there are rarely enough minutes to get it done.)

Best,
Karl

[Norbert Preining]

HI Karl,

Post by Karl Berry
In theory, as Akira said, .fmt/etc files from web2c are and have been
100% portable across platforms, independent of endian-ness, Windows
vs. Unix-ness, and everything else. (I seem to recall that being one of
the first changes I made to web2c back in the mid/late-80s.)

Oh ... good.

Post by Karl Berry
There was a bug a few years ago, possibly present for more than one
year, where the format files were endian-dependent. That was never
intentionally the case.

Ah, this is what I remembered faintly ... or less faintly ;-)

Norbert

------------------------------------------------------------------------
PREINING, Norbert http://www.preining.info
JAIST, Japan TeX Live & Debian Developer
GPG: 0x860CDC13 fp: F7D8 A928 26E3 16A1 9FA0 ACF0 6CAC A448 860C DC13
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