[Octave-bug-tracker] [bug #63931] Binary fwrite writes incorrect data to file

[Arun Giridhar]

Follow-up Comment #31, bug #63931 (project octave):

I traced the flow from file-io.cc to two places, using Doxygen. One is a bunch
of base and instantiated write functions such as that in ov-magic-int.cc.
Ultimately those all call the second location anyway, which is where
stream::write is defined, as well as several instances of it. 

There's nothing that's obviously wrong, but this isn't an obvious bug. There
is one type conversion that happens around line 7084, which in turn calls
convert_data and in turn convert_chars orconvert_ints.

By eliminating most of the other possibilities, it must be going wrong in
lines like; 

vt_data[i] = val.value ();

where the value conversion must be getting messed up, and if it's but I have
no idea why (except suspecting saturation semantics) nor why it's
encoding-dependent.

Re bisection, you probably want "update default" and bound your search between
the first bump that starts off Octave 8 (right after 7.1 was made) and the one
that starts Octave 9 (right after 8.1 was made). I disabled most of my
libraries but couldn't prevent symbfact.cc from building and causing errors.
If you have better techniques I'll try them. 



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