[GiNaC-list] bug in ex::ex(const std::string&, const ex&)

[Richard B. Kreckel]

Hi Diego,

On 4/4/24 9:29 AM, Diego Conti wrote:
> The function dispatch_reader_fcn is precisely where the 
> pointer-to-integer conversion is made.
> 
> I can confirm that function alignment is the problem by logging the 
> address of sqrt_reader inside
> 
> the function get_default_reader (attached patch to default_reader.cpp).
> 
> This prints out 140737351734977 before crashing (without the pragma). 
> However, the code assumes that the address is even.
> 
> With the pragma, the code prints out
> 
> 140737351734992
> 
> sqrt(3)
> 
> and then exits normally.

The comments labelled KLUDGE in parser/parser.cpp hint at something 
wrong. I suppose that rather than adding a #pragma, this mechanism 
should be fixed. Right away, I don't see what's wrong with this as it 
seems to match encode_serial_as_reader_func() in default_reader.cpp:75.

I suppose the reason why it works with Autoconf but not with CMake is 
just different optimization: Autoconf turns on -O2 by default but CMake 
doesn't, so no optimization. It should of course work with any optimization.

All my best,
   -richy.

PS: It's great you care to send patches! Please consider creating them 
with context, i.e. using diff -u (as git diff does by default). It makes 
them much easier to read and apply.
-- 
Richard B. Kreckel
<https://in.terlu.de/~kreckel/>

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