[PPL-devel] Wrong arithmetic conversion
Abramo Bagnara
abramobagnara at tin.it
Wed Nov 8 10:50:19 CET 2006
When evaluating comparison expressions, the "usual arithmetic
conversions" mandated by C standard (ISO/IEC 9899 #6.3.1.8) are NOT done.
In the cases below note that GDB returns the mathematically correct
result, but this is not conforming to C standard and to GDB
documentation that says:
"The usual way to examine data in your program is with the `print'
command (abbreviated `p'), or its synonym `inspect'. It evaluates and
prints the value of an expression of the language your program is
written in"
GNU gdb Red Hat Linux (6.3.0.0-1.134.fc5rh)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
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There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "i386-redhat-linux-gnu"...Using host
libthread_db library "/lib/libthread_db.so.1".
(gdb) print (float)123456792.0 > 123456789
$1 = true
(gdb) print (float)123456792.0 > (float)123456789
$2 = false
(gdb) print 123456789123456784.0 < 123456789123456789LL
$3 = true
(gdb) print 123456789123456784.0 < (double)123456789123456789LL
$4 = false
--
Abramo Bagnara mailto:abramobagnara at tin.it
Opera Unica Phone: +39.0546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy
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