libstdc++/6268: _M_extract_buffer_length = 32 for double do_get

[kenta@mit.edu]

>Number:         6268
>Category:       libstdc++
>Synopsis:       _M_extract_buffer_length = 32 for double do_get
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 11 20:26:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     kenta@mit.edu
>Release:        3.0.4
>Organization:
>Environment:
i386 Linux (and others probably)
>Description:
In the "double" overloaded version of do_get()  (buried inside
i686-pc-linux-gnu/libstdc++-v3/include/bits/locale_facets.tcc), the comment
makes reference to "the size of 256" (line 595 for 3.0.3), but
the array __xtrc is declared to be of length 32 (i.e.,
_M_extract_buffer_length).  This is probably a bug.

As far as I can tell, this is what causes failure for
this simple code "double x; cin >> x" and I input

0.12345678901234567890123456789012345678901234567890

Anything more than 30 digits past the decimal point breaks.
I want it to gracefully round or truncate.







>How-To-Repeat:

>Fix:
Don't ever input more than 30 digits past the decimal point.
>Release-Note:
>Audit-Trail:
>Unformatted: